Alkali sulfate-activated blended cement

ABSTRACT

Described are cementitious reagent materials produced from globally abundant inorganic feedstocks. Also described are methods for the manufacture of such cementitious reagent materials and forming the reagent materials as microspheroidal glassy particles. Also described are apparatuses, systems and methods for the thermochemical production of glassy cementitious reagents with spheroidal morphology. The apparatuses, systems and methods make use of an in-flight melting/quenching technology such that solid particles are flown in suspension, melted in suspension, and then quenched in suspension. The cementitious reagents may be combined with Portland cement and an alkali activator to form a blended cement. The cementitious reagents can be used in concrete to substantially reduce the CO 2  emission associated with cement production.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-Part of U.S. application Ser. No.16/915,804 filed Jun. 29, 2020, which claims the benefit under 35 U.S.C.§ 119(e) of U.S. Provisional Application Ser. No. 62/867,480, filed Jun.27, 2019, U.S. Provisional Application Ser. No. 63/004,673, filed Apr.3, 2020, and U.S. Provisional Application Ser. No. 63/025,148, filed onMay 14, 2020, the disclosures of which are incorporated, in theirentirety, by this reference.

BACKGROUND

The field of the present disclosure is related to cementitious reagents,and more particularly, to the creation of relatively homogeneouscementitious reagent materials and cementitious materials from abundantheterogeneous feedstocks.

Concrete has played an important role in civilization for thousands ofyears and is still the most commonly used building material. Concretemay be formed by mixing water, aggregate (e.g., sand, gravel, and/orrock), and cement. Through a hydration process, hydraulic cements bindthe aggregate into a solid composite. Concrete may be characterized bythe type of aggregate or cement used, the properties it exhibits, or bythe methods used in its production.

Cement is the essential binding component of concrete that allowsflowable concrete slurries to harden into a useful composite material atambient temperatures. Many binder chemistries have been successfullyused to make concrete, but Portland cement and its variations have beenthe dominant concrete binder for almost 200 years. Despite advances inproduction efficiency and material performance, there are significantand intrinsic problems with Portland cement chemistry that cannot besolved at any reasonable cost by current methods.

Portland cement production is a CO₂ intensive process that causes about8% of global anthropogenic CO₂ emissions. Some estimates project thatcement demand will increase by 12-23% by 2050. However, the growingabsolute demand for cement is at odds with the need for completedecarbonization of the economy that is also required by 2050 to avoidcatastrophic effects of climate change, according to the UN IPCC ClimateReport 2018. There is therefore an urgent need for drastically loweringthe specific CO₂ emissions of cement, especially because absoluteproduction volume is increasing.

One way that the industry has tried to reduce the CO₂ emission of cementis by developing geopolymer cements, which are generally aluminosilicateinorganic polymers that cure through a geo-polymerization process.Commercially relevant geopolymer cements in use today include severalspecific solid reagents (commonly: metakaolin (MK-750), groundgranulated blast furnace slag (GGBFS), and coal fly ash). However, thesereagents cannot satisfy the global transition to low-CO₂ cements becausesupply is relatively limited in geography and volume compared to theenormous demand for cement. Also, the cost of shipping these productsfrom production locations is significant compared to their market value.

Cementitious reagents are useful in both hydraulic and geopolymercements. Geopolymer reagents, and supplementary cementitious materials(SCMs), are typically selected from several common cementitiousmaterials: byproduct ashes from combustion (e.g., coal fly ash), slagbyproducts (e.g., ground granulated blast furnace slag), calcined clays(e.g., metakaolin), and natural pozzolans (e.g., volcanic ash). Thesematerials are generally substantially non-crystalline and sometimesreactive in cementitious systems such as in geopolymeric systems.

Since the majority of SCMs that are used in blended hydraulic cementsare industrial by-products (e.g., coal combustion, or quality ironproduction), their material properties are a result of the industrialby-product and are not specifically tailored as a quality cementitiousreagent. Accordingly, these materials lack any guarantee of ideal oreven consistent composition and quality, and their suitability ascementitious reagents varies from plant to plant, and over time. Thereis also no control over production location, and the concrete industrylacks control over future availability of these critically importantcementitious materials. It would be much more advantageous if theproduction location could be chosen based on market needs, particularlybecause shipping of cementitious materials is very expensive.

Fly ash is a partially glassy aluminosilicate by-product of coalcombustion. It is frequently used as an admixture in hydraulic cementmixes to improve flowability and create a pozzolanic reaction to improveproperties of concrete including strength, resistance to alkali-silicareaction and others. Unfortunately, only certain coal and combustionprocesses create a consistent supply of fly ash of a quality acceptablefor use in concrete (e.g., ASTM Type C and Type F ash, or CSA Type C,CI, and F ashes). Ash is not produced as an optimal SCM; rather,combustion is optimized for power generation and pollution prevention:there is no guaranteed consistency of by-product ash. Further challengesfor the future of fly ash in concrete include a significant decrease inregional availability due to transition from coal energy to natural gasin many markets, carbon introduced post-combustion can negatively affectair entrainment in concrete, recovery of ash from impoundments willincrease cost, and quality must be verified through testing in eachcase.

Ground Granulated Blast Furnace Slag (GGBFS) is a glassy CaO—SiO₂by-product of iron production in blast furnaces. Concretes incorporatingGGBFS have many advantageous properties including improved chemicaldurability, whiteness, reduced heat of hydration, mitigation of CO₂footprint, and other beneficial properties. Unfortunately, the supply ofblast furnace slag is quite limited due to the small number of blastfurnaces operating in most markets. As such, GGBFS is in high demand asa quality and prices for this by-product are now similar to the price ofcement itself. Additionally, the limited geographic supply leads toshortages or at least high shipping costs for many local concretemarkets. Finally, iron production and resulting blast furnace slagsupply are not coupled directly to concrete demand, leaving supplyvolume, local availability, and market price of these importantadmixtures largely up to chance.

Natural pozzolans are siliceous or alumino-siliceous materials that areable to participate in the pozzolanic reaction with Ca(OH)₂. Theseinclude as-mined or calcined volcanic ash, diatomaceous earth, kaoliniteand other clays, MK-750 and other natural minerals and rocks that reactwith lime to produce a hydrated calcium silicate compound. Naturalpozzolans can be very effective SCMs in concrete, however they requiremining of non-renewable resources and pozzolans often requiresignificant shipping distances since deposits are not extremely common.Also, natural materials often require significant processing such ascalcining to enhance reactivity.

Fly ash (usually with low CaO content, as in type F), GGBFS, and certainnatural and processed “pozzolans” (e.g., volcanic ashes, zeolites, andMK-750) are also common geopolymer reagents, and the same unfortunatelimitations on supply, geographic availability, price, quality, andconsistency apply for their application in geopolymer binders andcements.

To overcome certain limitations of these existing SCM and geopolymerreagent supplies, several attempts have been made to improve on aspectsof traditional methods. Despite some improvements, these man-madeproducts or compositions still possess numerous deficiencies, forinstance with respect to reactivity and chemistry of reagents for use ingeopolymer chemistry (e.g., optimizing reagents to later produce highcoordination, branched, and three-dimensional alkali/alkaline earthaluminosilicate polymers). They also require expensive lab-gradereagents and cannot simply use globally abundant feedstocks.

Also, previously manufactured glassy cementitious reagents have angularor fibrous particle morphology. Thus, cement pastes made from suchreagents require a lot of water and have relatively poor workability(e.g., with excessive yield stress or higher than optimal plasticviscosity) which is a barrier to use in practical concrete applications.

Combustion ashes and silica fume typically do not have angular particlemorphology. However, these are not available in sufficient quantities,do not have appropriate chemistry, and/or are too expensive to support alarge-scale transition to high SCM blend hydraulic or geopolymercements.

There is thus a need for cementitious reagents that solve existingworkability issues with a similar degree of effectiveness as superplasticizers and water reducers in equivalent Portland cement mixdesigns. There is also a need for a method of reducing CO₂ emissions inproduction of Portland cement, and particularly, a need for anengineered cementitious reagent with low or zero process CO₂ emissionsthat can be used as a supplementary cementitious material in hydrauliccements, and/or as a solid geopolymer reagent.

There is also need for a cementitious reagent that can be producedubiquitously from globally abundant feedstocks, is reactive incementitious systems, and delivers workable low-yield stress cementmixes.

Furthermore, there is a need for production of cementitious reagentswherein the production location could be chosen based on market needs.There is particularly a need for non-angular particle or microspheroidalglassy particles useful in cementitious reagents, geopolymer reagents,supplementary cementitious materials (SCM), cement mixes and concrete.

There is also a need for the economical production of suchmicrospheroidal glassy particles, e.g., by using globally abundantfeedstocks. There is also a need for apparatuses, systems and methodsusing in-flight melting/quenching such wherein solid particles are flownin suspension, melted in suspension, and then quenched in suspension.

The dominant cement used in concrete today is a hydration-curing calciumsilicate product known as Portland cement. Unfortunately, manufacture ofPortland cement clinker causes CO₂ process emissions (from heatinglimestone) that are globally impactful (about 3-5%, not countingfuel-derived GHG emissions). The process is carried out in a rotary kilnwith raw meal flowing countercurrent to the kiln burner. The process isvery energy intensive, consuming ˜3-5 GJ/ton, of which about 1.5 GJ/tonis spent simply calcining limestone. Of the few viable strategies todecrease environmental impact of cement, geopolymer chemistry provides aglobally viable alternative cement with improved environmental andmaterial performance. The inconsistent supply and limited geographicavailability of traditional geopolymer reagents such as fly ash andslags have limited standardization and adoption of geopolymer concretes.On the other hand, an increasing demand for supplementary cementitiousmaterials (SCM) in hydraulic cements (to enhance material andenvironmental performance) has further squeezed demand for thesematerials.

Various approaches have been used to manufacture cementitious reagents.However, these methods suffer from crucial deficiencies that haveprevented an economic manufacturing process for glassy cementitiousreagents. For instance, high-temperature refractory-lined furnaces andcrucibles have been used to directly contain glass melts in existingacademic research on cementitious reagents (a natural extension oftraditional glassmaking techniques). However, solid refractory materialsin crucibles and surrounding conventional furnaces require low heatingand cooling rates (order of 10-50° C./min) to avoid thermal shockbreakage. Conventional melting furnaces have high thermal mass whichmakes maintenance difficult and costly as a result of long startup andshutdown cycles. It is preferable to avoid the need for refractoriesthat directly contact the melt, so as to avoid, complexity, wear, andalso considerable start up and shut down times.

Quenching of molten glass for cementitious reagents (blast furnace slag,for example) has previously required water, which is costly, inhibitsheat recovery, could have negative environmental consequences, and mayrequire added complication of solid/liquid separation. Melt quenchingmethods were thus either wasteful or slow, diminishing reactivity.Air-quenching methods of cooling melts are either too slow or requirevery specific chemistry to ensure low melt viscosities of about 1 Pa-sor less, which is not feasible for most desired feedstock materials.

Previous glass manufacturing methods have required costly particle sizereduction (milling) of glassy product (typically before and afterthermal processing).

Accordingly, there is still a need for a convenient and economic methodof manufacturing a glassy cementitious reagent from globally abundantfeedstocks.

There is also a need to minimize energy consumption and cope with veryhigh and variable melt viscosity without requiring fluxes.

There is also a need for methods of producing microspheroidal glassyparticles and for apparatuses and systems useful for producing suchmicrospheroidal glassy particles.

SUMMARY

Embodiments relate to an alternative cement material (ACM), which insome embodiments includes solid microspheroidal glassy particles havingone or more of the following properties: mean roundness (R)>0.8 and lessthan about 40% particles having angular morphology (R<0.7).

In some embodiments, the particles have a mean roundness (R) of at least0.9. In embodiments, less than about 30% of the particles, or less thanabout 25% of the particles, or less than about 20% of the particles, orless than about 15% of the particles, or less than about 10% of theparticles have an angular morphology (R<0.7).

In some embodiments, the particles have the mean oxide Formula 1:(CaO,MgO)a.(Na₂O,K₂O)b.(Al₂O₃,Fe₂O₃)c.(SiO₂)d [Formula 1]; wherein a isabout 0 to about 4, b is about 0.1 to about 1, c is 1, and d is about 1to about 20.

In some embodiments, the particles further include one or more of thefollowing properties: (i) a content of 45%-100%, and preferably 90-100%,X-ray amorphous solid; and (ii) molar composition ratios of(Ca,Mg)₀₋₁₂.(Na,K)_(0.05-1).(Al, Fe³⁺)₁.Si₁₋₂₀.

According to another aspect, some embodiments relate to a cementitiousreagent including a mixture of microspheroidal glassy particles asdefined herein.

According to another particular aspect, some embodiments relate to acementitious reagent including a mixture of microspheroidal glassyparticles, these particles exhibiting one or more of the followingproperties: (i) mean roundness (R)>0.8; (ii) less than about 20%particles having angular morphology (R<0.7); (iii) the oxide Formula 1as defined hereinbefore; (iv) a content of 45%-100%, and preferably90-100%, X-ray amorphous solid; (v) a molar composition ratio of(Ca,Mg)₀₋₁₂.(Na,K)_(0.05-1).(Al, Fe³⁺)₁.Si₁₋₂₀; and (vi) a low calciumcontent of about <10 wt. % CaO, or an intermediate calcium content ofabout 10 wt. % to about 20% wt. % CaO, or a high calcium content of >30wt. % CaO.

In some embodiments, the cementitious reagent is in the form of anon-crystalline solid. In some embodiments, the cementitious reagent isin the form of a powder. In some embodiments, the particle sizedistribution with D[3,2] (i.e., surface area mean, or Sauter MeanDiameter) is about 20 μm or less, more preferably 10 μm or less, or mostpreferably 5 μm or less. In one embodiment, the mixture ofmicrospheroidal glassy particles of the cementitious reagent has theoxide Formula 1 as defined hereinabove. In some embodiments, thecementitious reagent includes less than about 10 wt. % CaO. In someembodiments, the cementitious reagent includes more than about 30 wt. %CaO. In some embodiments the cementitious reagent is about 40-100% andpreferably about 80% X-ray amorphous, 90% X-ray amorphous, and up toabout 100% X-ray amorphous, and in some embodiments, is 100%non-crystalline.

According to some embodiments, a geopolymer binder includes acementitious reagent as defined herein. According to another particularaspect, some embodiments relate to a supplementary cementitious material(SCM) including a cementitious reagent as defined herein, for instance aSCM including at least 20 wt. % of the cementitious reagent.

According to another particular aspect, some embodiments relate to asolid concrete including a cementitious reagent as defined herein.

According to another particular aspect, some embodiments relate to theuse of microspheroidal glassy particles as defined herein, and to theuse of a cementitious reagent as defined, to manufacture a geopolymerbinder or cement, a hydraulic cement, a supplementary cementitiousmaterial (SCM) and/or solid concrete.

According to another particular aspect, some embodiments relate to amethod for producing a cementitious reagent from aluminosilicatematerials, including the steps of: (i) providing a solid aluminosilicatematerial; (ii) in-flight melting said solid aluminosilicate material tomelt said material into a liquid and thereafter in-flight quenching saidliquid to obtain a powder including solid microspheroidal glassyparticles, thereby obtaining a cementitious reagent with said powder ofmicrospheroidal glassy particles.

In some embodiments, the method further including: (iii) of grindingsaid powder of microspheroidal glassy particles into a finer powder. Inone embodiment, the powder has a particle size distribution with D[3,2]of about 20 μm or less, more preferably 10 μm or less, or mostpreferably 5 μm or less.

In some embodiments, the cementitious reagent obtained by the methodincludes one or more of the following properties: reactivity incementitious systems and/or in geopolymeric systems; delivers workablelow yield stress geopolymer cement mixes below 25 Pa when a cement pastehas an oxide mole ratio of H₂O/(Na₂O,K₂O)<20; has a water content in acement paste such that the oxide mole ratio H₂O/(Na₂O,K₂O)<20; and formsa cement paste with higher workability than an equivalent paste withsubstantially angular morphology, given the same water content.

Throughout the instant specification, the term “substantially” inreference to a given parameter, property, or condition may mean andinclude to a degree that one of ordinary skill in the art wouldunderstand that the given parameter, property, or condition is met witha small degree of variance, such as within acceptable manufacturingtolerances. By way of example, depending on the particular parameter,property, or condition that is substantially met, the parameter,property, or condition may be at least approximately 90% met, at leastapproximately 95% met, or even at least approximately 99% met.

In some embodiments, the method further includes the step of adjustingcomposition of a non-ideal solid aluminosilicate material to a desiredcontent of the elements Ca, Na, K, Al, Fe, and Si. In one embodiment theadjusting includes blending a non-ideal aluminosilicate material with acomposition adjustment material in order to reach desired ratio(s) withrespect to one or several of the elements Ca, Na, K, Al, Fe, and Si.

In some embodiments, the method further includes the step of sorting thesolid aluminosilicate material to obtain a powder of aluminosilicateparticles of a desired size. In some embodiments, the method furtherincludes the step of discarding undesirable waste material from saidsolid aluminosilicate material.

In some embodiments, the in-flight melting includes heating at atemperature above a liquid phase temperature to obtain a liquid. In someembodiments, the temperature is between about 1000° C. to about 1600°C., or between about 1300° C. to about 1550° C.

In some embodiments, the method further includes the step of adding afluxing material to the solid aluminosilicate material to lower itsmelting point and/or to induce greater enthalpy, volume, ordepolymerization of the liquid. In some embodiments, the fluxingmaterial is mixed with the solid aluminosilicate material prior to, orduring the melting.

In some embodiments, the in-flight melting/quenching includes reducing atemperature of the liquid below a glass transition temperature toachieve a solid. In some embodiments, the in-flight melting/quenchingincludes reducing a temperature of the liquid below about 500° C., orpreferably below about 200° C., or lower. In some embodiments, reducinga temperature of the liquid includes quenching at a rate of about 10²Ks⁻¹ to about 10⁶ Ks⁻¹, preferably at a rate of >10^(3.5) Ks⁻¹. In someembodiments, quenching includes a stream of cool air, steam, or water.In one embodiment, the method further includes separating quenched solidparticles from hot gases in a cyclone separator.

In some embodiments, the method for producing a cementitious reagentfrom aluminosilicate materials may additionally include reducingparticle size of the powder of solid microspheroidal glassy particles.In some embodiments reducing particle size may include crushing and/orpulverizing the powder in a ball mill, a roller mill, a vertical rollermill or the like.

According to another aspect, some embodiments relate to an apparatus forproducing microspheroidal glassy particles, the apparatus including aburner, a melting chamber and a quenching chamber. The melting chamberand the quenching chamber may be completely separate or may be first andsecond sections of the same chamber, respectively. The apparatus may beconfigured such that solid particles are flown in suspension, melted insuspension, and then quenched in suspension in the apparatus.

In some embodiments, the burner provides a flame heating solid particlesin suspension to a heating temperature sufficient to substantially meltsaid solid particles into a liquid. In some embodiments, the burnergenerates a flame that is fueled with a gas that entrainsaluminosilicate feedstock particles towards the melt/quench chamber. Thegas may include an oxidant gas and a combustible fuel. In someembodiments the burner may include at least one of a plasma torch, anoxy-fuel burner, an air-fuel burner, a biomass burner, and a solarconcentrating furnace.

In some embodiments, the quenching chamber of the apparatus includes acooling system for providing cool air inside the quenching chamber, thecool air quenching molten particles to solid microspheroidal glassyparticles. In some embodiments, the cooling system includes a fluid(e.g., gas- or liquid-containing) cooling loop positioned around thequenching chamber.

In some embodiments, the apparatus may include one or more of a cycloneseparator, a baghouse chamber, and an electrostatic precipitator (ESP)for collecting the microspheroidal glassy particles. A cyclone separator(or cyclone) is a centrifugal device in which microspheroidal glassyparticles, due to their mass, may be directed by centrifugal force tothe periphery of a cyclone chamber and may exit the chamber via acollection device fitted to the separator. A baghouse chamber, which maybe operated in conjunction with a cyclone separator, includes an inletfor receiving a gas stream containing microspheroidal glassy particles,an outlet for exiting the gas stream after filtering, and a main chamberlocated between the inlet and the outlet. At least one filter bag may behoused within the main chamber for filtering the gas stream, i.e., forseparating the microspheroidal glassy particles from the conveying gasstream. The filter bag may include a fabric filter bag, for example. Anelectrostatic precipitator may remove microspheroidal glassy particlesfrom a conveying gas stream by using electrical energy to apply anelectric charge to the particles. The charged particles may then beattracted to collector plates carrying an opposite charge.

According to some embodiments, a method for producing microspheroidalglassy particles includes: providing an in-flight melting/quenchingapparatus including a burner, a melting chamber and a quenching chamber;providing solid particles; flowing said solid particles in suspension ina gas to be heated by said burner; heating said solid particles intosaid melting chamber to a heating temperature above liquid phase toobtain liquid particles in suspension; and quenching said liquidparticles in suspension to a cooling temperature below a liquid phasetemperature to obtain a powder including solid microspheroidal glassyparticles.

In some embodiments of these methods, the solid particles includealuminosilicate materials. In some embodiments of these methods, theheating temperature is between about 1000° C. to about 1600° C., orbetween about 1300° C. to about 1550° C. In some embodiments of thesemethods, the cooling (quench) temperature is below about 500° C., orbelow about 200° C. In some embodiments of these methods, the quenchingincludes providing cool air inside the quenching chamber. In someembodiments, these methods further include collecting the powder with acollection system.

As disclosed herein, a blended cement may include a mixture ofmicrospheroidal glassy particles and Portland cement. The blended cementmay additionally include an alkali activator and optionally analuminum-containing reagent such as metakaolin.

Additional aspects of some embodiments relate to the use of an apparatusas defined herein, particularly an apparatus including at least one of aplasma torch, an oxy-fuel burner, an air-fuel burner, a biomass burner,and a solar concentrating furnace, for producing microspheroidal glassyparticles using in-flight melting/quenching.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the features, advantages and principles of thepresent disclosure will be obtained by reference to the followingdetailed description that sets forth illustrative embodiments, and theaccompanying drawings of which:

FIG. 1 is a flow diagram showing production of a cementitious reagentstarting from a solid aluminosilicate material, in accordance with someembodiments;

FIG. 2 is a set of four ternary CaO, MgO—SiO₂—(Na₂O, K₂O)—(Al₂O₃, Fe₂O₃)composition diagrams, in accordance with some embodiments;

FIG. 3 is a three-dimensional quaternary diagram in (CaO, MgO)—(Al₂O₃,Fe₂O₃) (Na₂O, K₂O)—(SiO₂) space using the same material compositionaldata plotted in FIG. 2, in accordance with some embodiments;

FIG. 4 is a particle size distribution graph comparing angular andspheroidal particle size distributions for commercially availablenatural volcanic glass powder (angular morphology) and particlesproduced in accordance with Example 1 (spheroidal morphology).Percentage of particles by volume below a given diameter (y axis) isprovided as a function of particle diameter in micrometers (x axis).Electron micrographs demonstrate particle morphology of the samples.

FIG. 5 is a graph providing a comparison of particle roundness (R)distributions of various powders, in accordance with some embodiments;(211-218, 519, 520, as defined hereinafter) before processing (501) andafter processing (502) in accordance with Examples 1-8, in accordancewith some embodiments. Image analysis was used to determine R valuesfrom micrographs of the same powders shown in FIG. 6 and FIG. 7following the method of Takashimizu & Liyoshi (Takashimizu, Y., Iiyoshi,M. (2016). New parameter of roundness R: circularity corrected by aspectratio. Progress in Earth and Planetary Sciences 3, 2.https://doi.org/10.1186/s40645-015-0078-x). Also see Table 17 for moreprecise data. For convenience, two Type F fly ash samples are alsoincluded; 519 (B-FA) a beneficiated fly ash sold commercially, and 520(L FA) an un-beneficiated fly ash direct from a coal power plant.

FIG. 6 is a panel showing a collection of electron micrograph pairscomparing unprocessed particles (501) and processed particles (502) fromvarious materials (211-218 as defined hereinafter) as described inExample 1 through Example 8. Field of view width for individual panelsis 140 μm.

FIG. 7 is a panel showing pictures of two Type F fly ashes, one directlyfrom a coal power plant in Nova Scotia (L-FA; 520) and anothercommercially available fly ash that has been beneficiated to removeactivated carbon and other contaminants (B-FA; 519). Field of view widthfor individual panels is 140 μm.

FIG. 8 is a schematic process flow diagram of a system to produce aglassy microspheroidal cementitious reagent, in accordance with oneembodiment.

FIGS. 9A and 9B are a photograph and a corresponding illustration,respectively of a burner flame (bottom) entering a melt/quench chamber(top) with entrained aluminosilicate feedstock particles, in accordancewith one embodiment.

FIG. 10 is a schematic drawing of an improved in-flight meltingapparatus that includes heat recovery loops for decreasing energy inputand CO₂ emissions, in accordance with one embodiment.

FIG. 11 illustrates the complete set of ternary representations of aNovel Composition closed to Si, Al, Fe, Ca+Mg and Na+K; in accordancewith some embodiments;

FIG. 12 illustrates ternary diagrams for a Novel Composition from the Siperspective; in accordance with some embodiments;

FIG. 13 illustrates ternary diagrams for a Novel Composition from the Alperspective; in accordance with some embodiments;

FIG. 14 illustrates ternary diagrams for a Novel Composition from the Feperspective; in accordance with some embodiments;

FIG. 15 illustrates ternary diagrams for a Novel Composition from theCa+Mg perspective; in accordance with some embodiments;

FIG. 16 is a schematic flow diagram describing the process of making analternative cement concrete using a relatively small decentralizedin-flight mini kiln, in accordance with some embodiments;

FIG. 17 is a schematic diagram showing conventional cement and aggregatedistribution in a modern centralized Portland cement kiln supply chain,in accordance with some embodiments;

FIG. 18 is a schematic diagram showing the transportation advantages ofcollocating alternative cement material (ACM) mini kilns at aggregatequarries in a novel decentralized method, in accordance with someembodiments;

FIG. 19 is a schematic diagram showing the transportation advantages ofcollocating alternative cement material (ACM) mini kilns at concretebatch plants in a novel decentralized method, in accordance with someembodiments; and

FIG. 20 is a schematic diagram showing the transportation advantages oflocating alternative cement material (ACM) mini kilns in a noveldecentralized manner at independent sites in the vicinity of aggregatequarries and concrete batch plants, in accordance with some embodiments.

DETAILED DESCRIPTION

The following detailed description provides a better understanding ofthe features and advantages of the inventions described in the presentdisclosure in accordance with the embodiments disclosed herein. Althoughthe detailed description includes many specific embodiments, these areprovided by way of example only and should not be construed as limitingthe scope of the present disclosure.

In the following description of the embodiments, references to theaccompanying drawings are by way of illustration of an example by whichembodiments may be practiced. It will be understood that otherembodiments may be made without departing from the scope of theinvention disclosed.

Microspheroidal Glassy Particles

Some embodiments relate to the production and uses of solidmicrospheroidal glassy particles. As explained with more detailshereinafter, a related aspect concerns a cementitious reagent includinga mixture or plurality of such microspheroidal glassy particles.

In accordance with various embodiments, the solid microspheroidal glassyparticles are appreciably round particles of high sphericity. As usedherein, the term “roundness” and corresponding unit “R” refer toroundness as defined by Takashimizu & Iiyoshi (2016). The valuesrequired to calculate R can be determined by performing image analysison appropriate photomicrographs of powders. R (roundness) provides aconvenient quantitative measure of roundness that is highly correlatedwith Krumbein's “roundness” (Krumbein, W. C. (1941) Measurement andgeological significance of shape and roundness of sedimentary particles.Journal of Sedimentary Petrology 11:64-72.https://doi.org/10.1306/D42690F3-2B26-11D7-8648000102C1865D.)

In some embodiments, the microspheroidal glassy particles have meanroundness (R) of at least 0.9 (standard deviation<0.15). In someembodiments, the microspheroidal glassy particles have bulk roundness(R) of at least 0.8 (standard deviation<0.15). In some embodiments, themicrospheroidal glassy particles have bulk roundness (R) of at least0.7, or 0.6, or 0.5 (standard deviation<0.15).

In some embodiments, a mixture of microspheroidal glassy particlesincludes less than about 50% particles, or less than about 40%particles, or less than about 30% particles, or less than about 25%particles, or less than about 20% particles, or less than about 15%particles, or less than about 10% particles having angular morphology(e.g., R<0.7).

In some embodiments, a mixture or plurality of microspheroidal glassyparticles is provided in a powder form having a particle sizedistribution with D[3,2] of about 20 μm or less, more preferably about10 μm or less, or most preferably about 5 μm or less.

In some embodiments, microspheroidal glassy particles are anon-crystalline solid.

In some embodiments, the microspheroidal glassy particles may becharacterized as an oxide material having a composition represented byFormula 1: (CaO,MgO)a.(Na₂O,K₂O)b.(Al₂O₃,Fe₂O₃)c.(SiO₂)d, wherein a isabout 0 to about 4, b is about 0.1 to about 1, c is 1, and d is about 1to about 20.

In some embodiments, the microspheroidal glassy particles include one ormore of the following properties: (i) a content of 45%-100%, andpreferably 90-100%, X-ray amorphous solid; and (ii) molar compositionratios of (Ca,Mg)₀₋₁₂.(Na,K)_(0.05-1).(Al, Fe³⁺)₁.Si₁₋₂₀.

In some embodiments, the microspheroidal glassy particles are 40-100%X-ray amorphous, more preferably about 80 to about 100% X-ray amorphous,and in some embodiments is 100% non-crystalline.

In some embodiments, the particles include less than about 10 wt. % CaO.In some embodiments, the particles include more than about 30 wt. % CaO.In some embodiments, the particles include a high-calcium content with amolar composition of Si/(Fe³⁺,Al) between 1-20, and CaO content of about10 wt. % to about 50 wt. %, preferably about 20-45 wt. %. In someembodiments, the particles include an intermediate-calcium content witha molar composition of Si/(Fe³⁺,Al) between 1-20, and CaO content ofabout 10 wt. % to about 20 wt. %.

As described hereinafter, the microspheroidal glassy particles mayadvantageously be produced from globally abundant inorganic feedstockssuch as aluminosilicate material. As used herein, the term“aluminosilicate material” refers to a material including oxides ofaluminum or aluminum and iron, and silicon dioxide selected from naturalrocks and minerals, dredged materials, mining waste including rocks andminerals, waste glass, aluminosilicate-bearing contaminated materialsand alumino-siliceous industrial by-products. An aluminosilicatematerial is preferably in the form of a crystalline solid (e.g., atleast 50 wt. %, or at least 60 wt. %, or at least 70 wt. %, or at least80 wt. %, or at least 90 wt. %, or 100 wt. % crystalline solid). In someembodiments, the aluminosilicate material includes at least 2 wt. %(Na₂O,K₂O), or at least 3 wt. % (Na₂O,K₂O), or at least 4 wt. %(Na₂O,K₂O), or at least 5 wt. % (Na₂O,K₂O), at least 6 wt. % (Na₂O,K₂O),or at least 7 wt. % (Na₂O,K₂O), or at least 8 wt. % (Na₂O,K₂O), or atleast 10 wt. % (Na₂O,K₂O), or at least 12 wt. % (Na₂O,K₂O), or at least15 wt. % (Na₂O,K₂O), or at least 20 wt. % (Na₂O,K₂O). In some instances,the inorganic feedstocks are heterogeneous, and the glassy particlesproduced are more homogeneous than the feedstock, as shown duringpartial homogenization during melting. That is, more than 10% of theparticles produced fall within a new intermediate formulation range.

In some embodiments the aluminosilicate material may be selected fromdredged sediments, demolished concrete, mine wastes, glacial clay,glacial deposits, fluvial deposits, rocks and mineral mixtures, forinstance rocks and mineral mixtures composed of some or all the elementsCa, Mg, Na, K, Fe, Al and Si. These aluminosilicate materials are widelyabundant in many different geographic regions.

As described hereinafter, the elemental composition of the feedstock maybe analyzed and chosen for desired uses. The feedstock may be analyzedby quantitative or semi-quantitative methods such as XRF, XRD, LIBS,EDS, wet chemical analysis, and various other existing methods todetermine the feedstock elemental composition.

As described hereinafter, the microspheroidal glassy particles may beproduced using a process or method for in-flight thermochemicalprocessing such as in-flight melting/quenching and/or suspensionmelting, for melting into a liquid the starting inorganic materials andthereafter quenching the liquid into solid particles. As used herein,the term “in-flight melting/quenching” or “suspension melting” refers toa process wherein solid particles are flown in suspension, melted insuspension, and then quenched in suspension to obtain a powder.

In some embodiments, the term “microspheroidal glassy particles”encompasses particles as defined hereinabove that are found in thepowder resulting directly from an in-flight melting/quenching process.In embodiments, the term “microspheroidal glassy particles” refers toparticles obtained after grinding or milling (e.g., using a jaw crusher,an impact mill, etc.) of the powder obtained after the in-flightmelting/quenching process.

As described hereinafter, the microspheroidal glassy particles find manyuses including, but not limited to, the preparation of cementitiousreagents, the preparation of geopolymer binders or cements, thepreparation of hydraulic cements, the preparation of supplementarycementitious materials (SCMs), and in the manufacture of solid concrete.One additional use may be as a fertilizer or soil amendment, e.g., as asubstitute to “rock dust.”

Cementitious Material

Some embodiments described herein relate to cementitious reagent powdersincluding microspheroidal glassy particles as defined herein.

Some embodiments also relate to geopolymer binders or cements, hydrauliccements, supplementary cementitious materials (SCMs), hydraulic concretemixtures, and solid concrete powders including microspheroidal glassyparticles as defined herein.

Particle morphology may have a considerable impact on physicalproperties and handling of cement slurries. Accordingly, thehigh-roundness morphology of the particles advantageously may provideincreased workability, fluidity, and/or decreased water demand forgeopolymer cement mixes. In particular, having high degrees of roundnessreduces yield stress and viscosity of cement mixes by reducinginterparticle friction. Additionally, spheroidal morphology may decreasewater demand by improving packing for a given particle sizedistribution.

As illustrated in FIGS. 2 and 3, the composition of cementitiousreagents in accordance with embodiments is different from existingcementitious materials. Indeed, considering combinations of ternarycompositions of element groups (CaO, MgO), (Al₂O₃, Fe₂O₃), (Na₂O, K₂O),and (SiO₂), embodiments of a cementitious reagent 201 occupy a positionin these figures that is different and distinct from fly ash (C and F)202, ground-granulated blast-furnace slag (GGBS or GGBFS) 203,metakaolin 204, and Portland cement 205. Examples of specific feedstockcompositions are shown in FIG. 2: volcanic pumice 211 (Example 1),basalt 212 (Example 2), a second basalt 213 (Example 3), coal tailingssamples 214 (Example 4), dredged sediment 215 (Example 5), copperporphyry flotation tailings 216 (Example 6), demolished concrete 217(Example 7), dioritic aggregate crusher dust 218 (Example 8).

Advantageously, the cementitious reagent may be formulated from globallyabundant rock, minerals and compounds of suitable composition. In thisway, the abundant feedstock may not need to be shipped very far to aprocessing facility, or a cement plant. In some instances, a cementplant may be built at the feedstock location.

In some embodiments, a cementitious reagent includes a mixture ofmicrospheroidal glassy particles as defined herein and may becharacterized by one or more of the following properties: (i) is in theform of a non-crystalline solid; (ii) is in the form of a powder; (iii)has a particle size distribution with D[3,2] of about 20 μm or less,more preferably 10 μm or less, or most preferably 5 μm or less; (iv) hasthe oxide Formula 1, as defined hereinbefore; (v) a content of 45%-100%,and preferably 90-100%, X-ray amorphous solid; (vi) molar compositionratios of (Ca,Mg)₀₋₁₂.(Na,K)_(0.05-1).(Al, Fe³⁺)₁.Si₁₋₂₀; (vii) includesless than about 10 wt. % CaO; (viii) includes more than about 30 wt. %CaO; (ix) has a molar composition of Si/(Fe³⁺,Al) between 1-20, and aCaO content of about 10 to about 50 wt. %, preferably about 20-45 wt. %;(x) has a molar composition of Si/(Fe³⁺,Al) between 1-20, and a CaOcontent of about 10 to about 20 wt. %; (xi) is 40-100% X-ray amorphous,more preferably above 80%, above 90%, and in some cases, up to about100% X-ray amorphous, and in some cases, is 100% non-crystalline; (xii)has a particle size distribution with D[3,2] of about 20 μm or less,more preferably about 10 μm or less, or most preferably about 5 μm orless.

In some embodiments, the cementitious reagent includes less than about10 wt. % CaO. In some embodiments, the cementitious reagent includesmore than about 30 wt. % CaO. In some instances, the composition ofcementitious reagent with respect to molar ratio of (Na, K), and Ca maybe varied to obtain certain advantages depending on the binder. Forexample, a cementitious reagent with less than about 10 wt. % CaO may besuitable for use in heat-cured geopolymer and as a fly ash substitute.In the alternative, a cementitious reagent with greater than about 30wt. % CaO has hydraulic properties and may be added to geopolymer resinto allow ambient-temperature curing of geopolymer cements and maydirectly replace blast furnace slag in blended Portland cement. In somecases, the CaO content is lower than about 30 wt. % in order to reducethe CO₂ impact of cement by avoiding a need for decomposition ofcarbonate-sourced calcium.

In some embodiments, the cementitious reagent is a low-calciumcontaining cementitious reagent with a molar composition of Si/(Fe³⁺,Al)between 1-20, and with a CaO content of about 10 wt. % or less.Preferably such cementitious reagent is 40-100% X-ray amorphous, morepreferably about 80% to about 100% X-ray amorphous, and in someembodiments 100% non-crystalline. Such low-calcium containingcementitious reagent may find numerous commercial applications, forinstance, as a pozzolanic admixture in hydraulic cement, and/or as areagent in geopolymer binders and cements.

In some embodiments, the cementitious reagent is a high-calciumcontaining cementitious reagent with a molar composition of Si/(Fe³⁺,Al)between 1-20, and CaO content of about 10 to about 50 wt. %, preferablyabout 20-45 wt. %. Preferably such cementitious reagent is 40-100% X-rayamorphous, more preferably about 80 to about 100% X-ray amorphous, evenmore preferably 100% non-crystalline. Such a high-calcium containingcementitious reagent may find numerous commercial applications, forinstance as a hydraulic admixture in blended hydraulic cement, and/or asa reagent in geopolymer binders and cements.

In some embodiments, the cementitious reagent is an intermediate-calciumcontaining cementitious reagent with a molar composition of Si/(Fe³⁺,Al)between 1-20, and CaO content of about 10 to about 20 wt. %. Preferablysuch cementitious reagent is about 40-100% and preferably about 80% toabout 100% X-ray amorphous, and even more preferably 100%non-crystalline. Such an intermediate-calcium containing cementitiousreagent may find numerous commercial applications, for instance as acementitious reagent with desirable intermediate hydraulic andpozzolanic properties, particularly in ambient-curing geopolymerapplications.

In some embodiments, the Na,K content in the cementitious reagent isoptimized. This may be advantageous for SCM applications where free limein hydraulic cement will exchange with soluble alkalis and coordinatewith sialate molecules derived from cementitious reagent to create someextent of relatively stable alkali aluminosilicate polymerization thatgreatly improves chemical properties of traditional hydraulic cements.In embodiments, the Na,K content is chosen in accordance with theunderstanding that geopolymer reagents with significant Na,K content maybe implemented with less soluble silicate hardener than would otherwisebe used, thus decreasing the soluble silicate requirement (and cost) ofa geopolymer mix design.

Methods of Preparation

Microspheroidal glassy particles as defined herein, as well ascompositions including same such as cementitious reagents, geopolymerbinders or cements, hydraulic cements, supplementary cementitiousmaterials (SCMs), and concrete can be prepared using any suitable methodor process.

FIG. 1 shows exemplary steps to produce cementitious reagent fromaluminosilicate materials in accordance with some embodiments. Briefly,a finely divided aluminosilicate material powder 101 is selected and itschemical composition is analyzed 102 and evaluated. The feedstock may beanalyzed by any suitable quantitative or semi-quantitative methods suchas XRF, XRD, LIBS, EDS, wet chemical analysis, and various otherexisting methods to determine the feedstock elemental composition.

If the selected composition is not acceptable, the material isoptionally amended, blended (e.g., in a vessel prior to thermochemicalprocessing), for example, through addition of a composition adjustmentmaterial 104 (see hereinafter) or sorted 103 and any undesirable wastematerial may be discarded 105.

The resulting solid aluminosilicate material including a powder ofdesirable composition is next heated 106 and individual particles orparticle agglomerates are melted into a liquid in suspension. Next theliquid particles in suspension are quenched 107 to obtain a powderincluding solid microspheroidal glassy particles. Next, the powder isoptionally crushed and/or pulverized (partially or entirely) 108 if itis desired to reduce particle size and/or adjust reactivity and obtainthe cementitious reagent 109.

Regarding the addition of a composition adjustment material 104, as usedherein the term “composition adjustment material” refers to any solid orliquid material with a composition suitable for preferentially alteringthe bulk or surface composition of aluminosilicate material with respectto one or several of the elements Ca, Na, K, Al, Fe, and Si.

Composition adjustment materials that introduce calcium (Ca) may includecalcium salts such as CaCO₃, Ca(OH)₂, CaO, CaCl, CaF₂, calcium silicateminerals and compounds, calcium aluminum silicate minerals andcompounds, waste Portland cement products, waste hydraulic cementproducts, wollastonite, gehlenite, and other melilite group mineralcompositions.

Composition adjustment materials that introduce aluminum (Al) mayinclude aluminous rocks, minerals, soils, sediments, by-products, andcompounds including one or more of kaolinite, halloysite and otheraluminum-rich/alkali-poor clay minerals, Al₂SiO₅ polymorphs, chloritoid,staurolite, garnet, corundum, mullite, gehlenite, diaspore, boehmite,gibbsite, and nepheline and other feldspathoids. Other materials thatmay be used include aluminum metal, bauxite, alumina, red mud (aluminarefinery residues).

Composition adjustment materials that introduce iron (Fe) may includeiron-rich rocks, minerals, soils, sediments, by-products, and compoundssuch as olivine, chlorite minerals (chamosite, clinochlore, etc.),pyroxenes, amphiboles, goethite, hematite, magnetite, ferrihydrite,lepidicrocite and other iron oxy-hydroxide compositions, iron-rich clayand phyllosilicate minerals, iron ore tailings, and elemental iron.

The heating 106 is carried out to reach a heating temperature above aliquid phase temperature to obtain a liquid, for instance at about 1000°C. to about 1600° C., or about 1300° C. to about 1550° C. Any suitablemethod or apparatus may be used for the heating and for obtaining theliquid including, but not limited to, in-flight melting (i.e.,suspension melting). This may be achieved by using an in-flight meltingapparatus equipped with, for instance, one or more plasma torches,oxy-fuel burners, air-fuel burners, biomass burners, a solarconcentrating furnace. Typically, a furnace temperature of 1000° C. toabout 1600° C. is needed, and most typically 1300° C. to about 1550° C.,to rapidly obtain the desired liquid phase particles in suspension. Inembodiments, the device is selected such that melting is as fast aspossible. An example of a suitable in-flight melting apparatus andmethod is described hereinafter.

In some embodiments the quenching step 107 includes reducing temperatureof the liquid below the glass transition, for instance at about 500° C.or lower, or preferably below about 200° C. or lower. In embodiments,the quenching is done rapidly, i.e., the temperature is reduced at arate of about 10²-10⁶ Ks⁻¹ (preferably at a rate of >10^(3.5) Ks⁻¹). Anysuitable method may be used for the quenching including, but not limitedto, contacting the molten material with a sufficient stream ofadequately cool air, with steam, or with water to produce anon-crystalline solid.

If desired, a fluxing material may be added to the solid aluminosilicatematerial in order to lower its melting point and/or to inducedepolymerization of the liquid. The fluxing material may be mixed withthe solid aluminosilicate material prior to heating/melting or duringthe heating/melting. Common fluxing materials that may inducedepolymerization in melts, and/or lower melting temperature includesCaF₂, CaCO₃, waste glass, glass cullet, glass frit, alkali-bearingminerals (e.g., feldspars, zeolites, clays, and feldspathoid minerals),borate salts, halogen compounds (fluoride and chloride bearing salts)and calcium salts.

Regarding the optionally crushing and/or pulverization step 108, thismay be carried out using any suitable method or apparatus including, butnot limited to, a ball mill, a roller mill and a vertical roller mill.Preferably the particle size is reduced to obtain a fine powder usefulin cementitious applications. Obtaining a finer powder may be useful forincreasing surface area and providing for faster reaction rates, asdescribed for instance in Example 9. Those skilled in the art will beable to determine the size of the particles desired for a particularneed, taking into consideration an economic trade-off between loss ofspherical morphology/workability, cost of grinding, and finalperformance requirements. In embodiments, the powder has a particle sizedistribution with D[3,2] of approximately 10 μm or less, or preferably 5μm or less. Such a particle size is generally desirable to ensuresufficient reactivity and consistent material properties.

Uses of Aluminosilicate Materials

As described herein, some embodiments concern the use of aluminosilicatematerials to produce solid microspheroidal glassy particles andnon-crystalline cementitious reagents as defined herein.

Another aspect is the use of in-flight thermochemical processing ofaluminosilicate materials to produce solid microspheroidal glassyparticles and/or solid cementitious reagents. The glassy particles andsolid cementitious reagents described herein may advantageously be usedas an alternative supplementary cementitious material (SCM) in blendedhydraulic cement and/or as a geopolymer solid reagent in geopolymerbinders (thus eliminating the need for some or all of MK-750, fly ash,GGBFS, and other common solid reagents).

Another related aspect is the use of an aluminosilicate material toproduce at least one of a supplementary cementitious material (SCM) anda geopolymer reagent including solid microspheroidal glassy particlesand/or a non-crystalline cementitious reagent as defined herein.

Uses of the Microspheroidal Glassy Particles and Cementitious Reagent

One aspect of described embodiments concerns the broad relevance of thesolid microspheroidal glassy particles and cementitious reagentsdescribed herein. Appropriate compositions of engineered cementitiousreagents may be used interchangeably in significant proportion in bothgeopolymer cements and hydraulic cements (i.e., cements that react withwater).

Accordingly, some embodiments encompass geopolymer cements and hydrauliccements including at least 5 wt. %, or at least 10 wt. %, or at least 15wt. %, or at least 20 wt. %, or at least 25 wt. %, or at least 30 wt. %,or at least 40 wt. %, or at least 50 wt. %, or at least 60 wt. %, or atleast 70 wt. %, or at least 80 wt. %, or at least 90 wt. %, or more, ofsolid microspheroidal glassy particles and/or cementitious reagent asdefined herein.

In accordance with some aspects, some embodiments described hereinrelate to a supplementary cementitious material (SCM) including acementitious reagent as defined herein. In some embodiments, the SCMincludes about 5 wt. % to about 50 wt. % (preferably at least about 20wt. %) of solid microspheroidal glassy particles and/or of thecementitious reagent.

In accordance with another aspect, some embodiments described hereinrelate to a supplementary cementitious material (SCM) including one ormore of the following properties: less than about 35 wt. % CaO, withappreciable content of Na+K (e.g., at least 2 wt. %, preferably at least5 wt. %) and Al content (e.g., at least 5 wt. %) and is in the form of anon-crystalline solid.

In accordance with another aspect, some embodiments relate to a solidconcrete, including solid microspheroidal glassy particles and/or acementitious reagent as defined herein, i.e., including about 5 wt. % toabout 50 wt. % (preferably at least 10 wt. %, or at least 20 wt. %,least 30 wt. %, or least 40 wt. %) of solid microspheroidal glassyparticles and/or the cementitious reagent.

In accordance with another aspect, some embodiments relate to solidgeopolymer concrete including about 5 wt. % to about 50 wt. %(preferably at least 10 wt. %, or at least 20 wt. %, at least 30 wt. %,or at least 40 wt. %) of solid microspheroidal glassy particles and/orcementitious reagent.

Those skilled in the art can appreciate that various embodimentsadvantageously provide methods to produce versatile low-CO₂ cementitiousreagents from abundant, cheap, natural materials. Another significantadvantage is the creation of a single reagent that meets specificationstandards for alternative SCMs, while also meeting the needs of thegrowing geopolymer market. Further, the cementitious reagents are formedfrom diverse, heterogeneous feedstocks, and through the describedprocesses, result in a reagent material that is more homogeneous andsuitable as a cementitious reagent.

As can be appreciated, one advantage of the systems and methodsdescribed herein is to provide control over the final composition of thecementitious reagent, thereby producing a reagent with predictablecomposition, which is very important to the industry. Such tailoredcomposition is not available in other existing cementitious reagents,because they are typically obtained from industrial by-products. Inaccordance with embodiments described herein, it is possible to modifylocal feedstocks to standardize performance for given applications. Forexample, in SCM for Portland cement it may be desirable to limit alkalicontent, but in geopolymer systems it may be desirable to have highalkali content and lessen the need for an alkali silicate hardener. Inboth scenarios, composition modifications may be desirable to limitcompositional variability of the feedstock.

Another notable concern for the chemistry of geopolymer reagents islabile calcium content. Adjustment of calcium content and phasescontaining calcium are both important variables for adjusting rate ofstrength gain under different temperature conditions and final materialproperties of geopolymer cement. The methods described herein make itpossible to engineer certain advantageous compositions ofmicrospheroidal cementitious reagents, which is not currently possiblefor by-product-based cementitious reagents.

In-Flight Melting Apparatus, Method, and System

Embodiments also relate to an apparatus, a system, and related methodsfor the thermochemical production of glassy cementitious reagents havinga spheroidal morphology.

According to some embodiments, an apparatus is configured for in-flightmelting/quenching. According to some embodiments, such as thoseillustrated in FIGS. 9A and 9B, the apparatus 900 includes a burner 809and a melting chamber combined with a quenching chamber 902. In someembodiments the melting chamber and the quenching chamber may be firstand second sections of the same chamber 902, respectively. In someembodiments, the melting chamber and the quenching chamber are separateconsecutive chambers.

As illustrated, the apparatus 900 is configured for in-flightmelting/quenching. Aluminosilicate feedstock particles 903 enter themelt/quench chamber (top; 902) suspended in a flame 901 combusting anoxidant gas 807 with a combustible fuel 808. The aluminosilicatefeedstock particles 903 are entrained by a venturi eductor into theoxidant gas and flow in suspension during combustion towards themelt/quench chamber 902 as they become heated and eventually molten,above liquid phase transition. The gas may include an oxidant gas,including but not limited to oxygen, air mixed with a combustible fuel,including but not limited to propane, methane, liquid hydrocarbon fuels,coal, syngas, biomass, coal-water slurries, and mixtures thereof.Preferably the flame 901 is stabilized by an annular flow of quench air904 that protects the melt/quench chamber 902 and prevents particlesfrom sticking to inner wall 905 of the melt/quench chamber 902.

In the apparatus 900, molten particles are next quenched by cooling inair as the suspension becomes turbulent at an end of the melt/quenchchamber 902. Cooling/quenching of the molten particles may be providedby cool quench air introduced directly into the melt/quench chamber 902,and/or by an optional cooling system, for instance a gas- orliquid-containing cooling loop around a quenching section of themelt/quench chamber 902 (not shown). The molten particles may bequenched or cooled to a non-crystalline solid powder containingmicrospheroidal glassy particles.

The apparatus 900 can be used in various systems to produce a glassymicrospheroidal cementitious reagent. FIG. 8 illustrates one embodimentof a schematic process flow diagram of an exemplary system 800 forproducing a glassy microspheroidal cementitious reagent, which in somecases, produces a microspheroidal glassy reagent powder 109.

In the embodiment of FIG. 8, the system 800 includes a milling circuit801 to obtain an aluminosilicate feedstock powder 101. Coarsealuminosilicate feedstock material 802 is fed to a jaw crusher or impactmill 803 to produce a suitably sized feed 804 for fine grinding in aball mill 805. The resulting product is a finely divided aluminosilicatefeedstock powder 101.

The finely divided aluminosilicate feedstock powder 101 is nextentrained in an oxidant gas (e.g., oxygen) 807, and mixed with acombustible fuel (e.g., propane) 808 in a burner 809 that is fitted witha gas- or liquid-containing cooling loop 810 for long torch life.Ambient temperature quench air 811 is introduced, preferably near theburner 809, and flows down the outside of the melt/quench chamber 812walls for preventing molten particles from sticking to the walls of theburner 809. Wall cooling may be provided by the quench air, and/or by anoptional liquid cooling loop 813. Molten particles are quenched by coolquench air as the suspension becomes turbulent at the end of themelt/quench chamber. A cyclone separator 814, operated under suctionfrom a centrifugal blower 815 may be used to collect the microspheroidalglassy reagent powder 109.

The apparatus of FIG. 9 and system of FIG. 8 were used to produce solidmicrospheroidal glassy particles, and cementitious reagent including thesame, as defined herein and described in the following examples. Theoperating parameters involved an approximately stoichiometric combustionof propane and oxygen gases (exact mass ratio not measured). Powderedfeedstock 101 entered the burner from a pneumatic disperser fed by avibratory feeder. The suspension of feedstock and combustion airincluded an approximately equal mass of oxygen and powdered feedstock;for example, 1 g of aluminosilicate feedstock suspended in 1 g ofoxygen.

Those skilled in the art will appreciate that the illustrated apparatus,system and parameters are ones of many potential useful apparatus andsystems. For instance, in alternate embodiments, the solid particles flyin suspension in a carrier gas and are heated by one or more energysources. The energy for melting may be provided by one or a combinationof suitable high-temperature heat sources such as plasma (arc dischargeor inductively coupled), electrical induction heating, electricalresistance heating, microwave heating, solar irradiation, or heat fromchemical reactions (e.g., combustion). Several of these energy sourcesmay lower the CO₂ footprint of the process, but costs of CO₂ emissionsmust be weighed against the unique costs of each energy source. In manyjurisdictions today, the cheapest energy sources are based oncombustible hydrocarbon fuels. Therefore, the choice of energy source ismostly dictated by price and cost of CO₂ emissions in a givenjurisdiction. Current economic and political factors dictate thatpreferably, the solid particles fly in suspension in a gas such thatcombustion heats the solid particles to a temperature above the liquidphase transition.

Although an oxygen-fuel burner was used in the examples provided, thoseskilled in the art will appreciate that the choice of burner fuels is ofonly secondary importance as long as adequate heating occurs. Any sourceof heat from combustion, plasma, concentrated solar power, nuclear, andothers, are possible.

In some embodiments, an air-fuel burner is preferable to avoid the costof oxygen enrichment. When air, consisting of only about 23 wt. %oxygen, is combusted with fuels (propane or methane for example) theair-fuel ratio is much higher (˜4-5×) to maintain an approximatelystoichiometric combustion. A higher air-fuel ratio results in lowerflame temperatures. Therefore, it is preferable to adjust accordinglythe feedstock powder mass flow to ensure the particles are heated beyondtheir solidus, and preferably near or beyond their liquidus temperature(about 1000° C. to about 1600° C., and commonly greater than about 1200°C.).

FIG. 10 illustrates another embodiment of an apparatus and system forin-flight melting/quenching in accordance with embodiments describedherein. Feedstock 101 passes through valve 1002 and enters cyclone 1003where it is preheated by exchanging heat with hot gases flowing throughpipe 1026. In certain embodiments, a pre-heat temperature may beinsufficient to melt the feedstock 101, and may range, for example, fromabout 300° C. to about 800° C. Valve 1004 meters feedstock powder intohot gas (e.g., combustion air) flowing through pipe 1025. Combustion airand feedstock suspension is conveyed through a burner 1005 whereincombustible gas is introduced through pipe 1006. A cylindrical meltingchamber 1007 is configured to receive a hot stream of gas (e.g.,combustion gases) entrained with aluminosilicate particles in variousstages of melting 1008. The melting chamber 1007 includes a cylindricalshell 1009 of suitable material such as steel, and an inner lining ofsuitable refractory material 1010. The melting chamber 1007 is alsoprotected internally by a stream of cool air (primary quench air) 1011injected from an upper distribution ring 1012. Cooling air flows insidethe melting chamber 1007 around inner chamber walls in a laminar orswirling flow 1013 without mixing significantly with the central streamof molten suspended particles 1008. This airflow also protects the innerrefractory lining 1010 and limits heat loss.

Molten particles 1008 next enter a quenching chamber or quench zone 1014where particles interact with primary quench air 1013 and optionallysecondary cool quench air 1015 that passes through a distributor 1016and is injected 1017 into the quenching chamber 1014.

Quenched, hot solid particles 1018 flow suspended through pipe 1019 andare separated from hot gases in a cyclone separator 1020. Hot solidglassy particles pass through valve 1021, exchange heat with coolcombustion air 1024, and are separated in combustion air preheat cyclone1022. Valve 1023 regulates pressure and allows collection ofmicrospheroidal glassy product 109. The cyclone separators 1003, 1020,1022 also function as solid/gas heat exchangers for important heatrecovery loops that increase energy efficiency of the process. Pluralcyclone separators may be arranged in various configurations, such as inseries or in parallel. In cyclone 1020, hot gases from the meltingchamber 1007 are separated from solids and these gases preheat coolerfeedstock powder 101 before separation in cyclone 1003. Theheat-exchanged exhaust gas 1027 reports to a suitable exhaust system(for example, a baghouse and blower) or passes on to further stages ofheat exchange cyclones. In cyclone 1022, hot quenched particles 1018exchange heat with cool combustion air 1024 and the preheated combustionair is used to convey preheated feedstock powder into the meltingchamber 1007 thereby considerably reducing the amount of energy thatmust be added to achieve melting of the suspended particles.

EXAMPLES Example 1: Yield Stress Reduction with Synthetic SpheroidalParticles

To demonstrate the improvement to geopolymer cement mix viscosity, thefollowing procedure was employed. A commercially-available pulverizedvolcanic glass powder of oxide composition SiO₂-73.77%; Al₂O₃-11.82%,Fe₂O₃-1.42%; MgO-0.1%; CaO-0.28%; Na₂O-4.22%; K₂O-4.09% was obtainedhaving a D[3,2] mean particle diameter of 10 micrometers and angularmorphology typical of finely ground powders. The volcanic glass powdersample 402 (FIG. 4) was processed by the presently disclosed method ofin-flight melting in order to create a molten/quenched powder 403,having a D[3,2] mean particle size of 11 micrometers, and substantiallyspheroidal morphology characterized by roundness R>8 (see FIG. 4). Morespecifically, the natural volcanic glass powder (angular morphology) wasprocessed by the apparatus shown in FIG. 8 and FIG. 9. The burner was acommercial oxygen-propane burner model QHT-7/hA from Shanghai Welding &Cutting Tool Works with modified powder feeding, the burner fired into asteel melt chamber with water-cooled walls, and particle temperaturesexceeded the mean liquidus temperature of the material, about 1300° C.as estimated from compositional data. It is interpreted that liquidustemperature was exceeded based on i) the microspheroidal morphology thatresults from surface tension in a liquid phase, ii) homogeneouscomposition (under backscattered electron imaging) and iii) the absenceof unmolten or partially molten particles in the final reagent.

In this experiment, the burner was not sealed tightly to the meltchamber, and thereby cool quench air was allowed to rush in along thewalls of the melt chamber, only quenching the molten entrained powderafter sufficient residence time to allow melting. Quenched hot powderwas separated from hot combustion gases with a cyclone as shown in FIG.8 and glass powder was collected for testing. The resulting product inthis example is a highly spherical synthetic glass (D[3,2]=11micrometers) of equivalent composition and nearly equivalent particlesize distribution (FIG. 4) as the raw feedstock.

The microspheroidal mineral glass powder has a molar Si/(Al, Fe³⁺) of19.68, and molar cementitious reagent formula of(Ca,Mg)_(0.12).(Na,K)_(0.89).(Al, Fe³⁺)₁.Si_(19.68) and CaO of 0.28 wt.% (CaO,MgO of 0.38%).

The experiment compares two geopolymer reagents with particles ofequivalent composition and nearly equivalent particle size distribution(confirmed by laser diffraction particle size analysis, FIG. 4). Theonly drastically changed variable is particle morphology.

The powders were mixed separately as geopolymer binder pastes using thefollowing mix design optimized for minimal water use for angularvolcanic glass (“Mix A”):

A 99.5 g mixture is made containing 1.77 moles of water, 0.12 molesNa₂O+K₂O, 0.82 moles SiO₂ and 0.08 moles Al₂O₃+Fe₂O₃. The source ofAl₂O₃+Fe₂O₃ is the cementitious reagent glass or volcanic glass. Thesource of SiO₂ is also the cementitious reagent or volcanic glass andpotassium silicate. The source of potassium oxide is potassium silicateand potassium hydroxide. The oxide mole ratios of each mix are providedin Table 1, shown below.

Spheroidal Mix A was too fluid when mixed at the same mass proportionsas Angular Mix A, which had very poor workability even at very highwater contents of 40 wt. % H₂O. Surprisingly, Spheroidal Mix B,containing only 15 wt. % H₂O, had excellent workability as indicated bylow yield stress of ˜6 Pa.

The glassy spheroidal powder was remixed with an identical amount ofsolid reagent, but lower proportions of silicate hardener and water(“Mix B”):

A 79 g mixture was made containing 0.73 moles of water, 0.11 molesNa₂O+K₂O, 0.8 moles SiO₂ and 0.08 moles Al₂O₃+Fe₂O₃. The source ofAl₂O₃+Fe₂O₃ is the spheroidal cementitious reagent. The source of SiO₂is also the spheroidal cementitious reagent and potassium silicate. Thesource of potassium oxide is potassium silicate and potassium hydroxide.The oxide mole ratios of each mix are provided in Table 1, shown below.

A mini-cone slump test (as described by Tan et al. 2017) was employed todetermine the approximate yield stress for the angular powder Mix A(spread radius 24 mm), and the spheroidal powder Mix B (spread radius 60mm). The angular powder produced a non-shear-flowing mass withapproximate yield stress of 425 Pa or greater (as calculated by slumpflow equation 10 elaborated in Pierre et al. 2013 (Pierre, A., Lanos,C., & Estelle, P. (2013). Extension of spread-slump formulae for yieldstress evaluation. Applied Rheology, 23(6), 36-44). Surprisingly, thespheroidal mix had only 41% of the molecular water content of theangular mix (including water in soluble silicate hardener) yet producedan easily pourable resinous fluid with yield stress of onlyapproximately 6.5 Pa (as calculated by the spreading flow equation 2 inTan et al. 2017 (Tan, Z., Bernal, S. A., & Provis, J. L. (2017).Reproducible mini-slump test procedure for measuring the yield stress ofcementitious pastes. Materials and Structures, 50(6), 235).

TABLE 1 Oxide mole ratios of mixes Molar ratio Angular “Mix A”Spheroidal “Mix A” Spheroidal “Mix B” (Na₂O, K₂O)/SiO₂  0.14   0.14  0.14  SiO₂/(Al₂O₃, Fe₂O₃)  11.72   11.72  10    H₂O/(Al₂O₃, Fe₂O₃) 22.125  22.125  9.125 (Na₂O, K₂O)/(Al₂O₃, Fe₂O₃)  1.63   1.63   1.375H₂O/(Na₂O, K₂O)  15.65   15.65   7.05  H₂O in paste (wt .%)  40%   40%   15%  Yield Stress (Pa) 425   <1     6   

Angular Mix A and Spheroidal Mix B were heated and cured in a sealedcontainer at 80 degrees Celsius for 6 hours. The angular paste hardenedpoorly, likely due to the high water content, while the spheroidal pastehardened to a ceramic-like solid with a fine glossy surface.

Example 2: Basalt “FC”

Oligocene basaltic rock was sampled in Vancouver, BC. The mineralogy ofthe rock is dominated by plagioclase, diopside and a clay-like phasethat is likely a weathering product (Table 2, determined by XRD withRietveld refinement). The major element oxide composition is provided inTable 3.

TABLE 2 Mineralogy of basalt sample Phase Weight % albite-low (calcian)56.2 diopside 13.5 clay (montmorillonite model) 12.5 forsterite(ferrian) 5.0 Illite/muscovite 2M1 2.6 lizardite 1T 1.7 ilmenite 1.7quartz 1.6 calcite 1.5 ulvospinel (ferrian) 1.4

TABLE 3 Oxide Composition of basalt “FC” (XRF) Oxide Weight % SiO₂ 48.13Al₂O₃ 15.97 Fe₂O₃ 11.99 MnO 0.16 MgO 7.83 CaO 9.51 Na₂O 2.77 K₂O 0.5

The basalt was crushed in a jaw crusher, then pulverized in a disc mill,and further reduced in a ring mill to a powder with mean particle sizeof approximately 10 μm. The powder was fed through a vitrificationapparatus that heated the material through the liquid transition toapproximately 1450° C., followed by a rapid quenching step. Theresulting glass was 96.7% X-ray amorphous (Table 4).

TABLE 4 XRD-Rietveld analysis of basalt glass (corundum spike) PhaseWeight % amorphous 96.7 iron-alpha (from grinding media) 1.9 quartz 1.4

The microspheroidal basalt glass powder has a molar Si/(Al, Fe³⁺) of6.93, and molar cementitious reagent formula of(Ca,Mg)_(3.15).(Na,K)_(0.21).(Al, Fe³⁺)₁.Si_(6.93) and CaO of 9.51 wt. %(CaO,MgO of 17.3%).

Individual particles were observed to be highly spherical and meanroundness R is >0.8 (as defined previously), and D[3,2] is 10.5 μm.

A 131 g mixture is made containing 1.31 moles of water, 0.1 molesNa₂O+K₂O, 0.88 moles SiO₂ and 0.24 moles Al₂O₃+Fe₂O₃. The source ofAl₂O₃+Fe₂O₃ is the microspheroidal basalt powder prepared above. Thesource of SiO₂ is also the basalt powder and potassium silicate. Thesource of potassium oxide is potassium silicate and potassium hydroxide.The oxide mole ratios are provided in Table 5, shown below.

TABLE 5 Oxide mole ratios (Na₂O, K₂O)/SiO₂ 0.11 SiO₂/(Al₂O₃, Fe₂O₃) 3.67H₂O/(Al₂O₃, Fe₂O₃) 5.45 (Na₂O, K₂O)/(Al₂O₃, Fe₂O₃) 0.42 H₂O/(Na₂O, K₂O)13.76 Yield Stress (Pa) 21.7

A mini slump cone test was performed on the geopolymer cement paste andresulted in a flow diameter of 98.4 mm and a calculated yield stress of21.7 Pa. 110 g of sand was added to the paste, followed by 6 hours ofsealed curing at 80 degrees Celsius. The compressive strength of amortar sample cube was determined to be 19 MPa.

Example 3: Basalt “BD”

A commercially available powdered basalt “BD” has the oxide compositionprovided in Table 6, shown below.

TABLE 6 Oxide Composition of basalt “BD” (XRF) Oxide Weight % SiO₂ 49.77Al₂O₃ 14.42 Fe₂O 11.18 MgO 4.38 CaO 9.66 Na₂O 2.62 K₂O 0.63

The powder was fed through a vitrification apparatus that heated thematerial through a liquid phase change to approximately 1450° C.,followed by a rapid quenching step. Successful melting through theliquid phase was demonstrated for most particles by a highly sphericalbulk particle morphology.

The microspheroidal basalt reagent powder “BD” has a molar Si/(Al, Fe³⁺)of 7.84, and molar cementitious reagent formula of(Ca,Mg)_(2.66).(Na,K)_(0.23).(Al, Fe³⁺)₁.Si_(7.84) and CaO of 9.66 wt. %(CaO,MgO of 14.04%). Individual particles were observed to be highlyspherical and smooth, a roundness R greater than 0.8, and D[3,2] is 8.0μm as measured by laser diffraction.

A 116 g mixture was made containing 1.53 moles of water, 0.09 molesNa₂O+K₂O, 0.75 moles SiO₂ and 0.17 moles Al₂O₃+Fe₂O₃. The source ofAl₂O₃+Fe₂O₃ is the microspheroidal basalt powder prepared above. Thesource of SiO₂ is also the basalt powder and potassium silicate. Thesource of potassium oxide is potassium silicate and potassium hydroxide.The oxide mole ratios are provided in Table 7.

TABLE 7 Oxide mole ratios (Na₂O, K₂O)/SiO₂ 0.11 SiO₂/(Al₂O₃, Fe₂O₃) 4.41H₂O/(Al₂O₃, Fe₂O₃) 9.00 (Na₂O, K₂O)/(Al₂O₃, Fe₂O₃) 0.53 H₂O/(Na₂O, K₂O)18.06

110 g of sand was added to the mixture, and the sample was cast intocube molds, followed by 6 hours of sealed curing at 80 degrees Celsius.From three samples, the mean compressive strength of the mortar wasdetermined to be 27.4 MPa with standard deviation of 2.22 MPa.

Example 4: Coal Tailings

A coal tailings sample acquired from Cape Breton, NS includesapproximately 60% residual coal and 40% mineral material. The inorganicfraction has the oxide composition provided in Table 8, shown below.

TABLE 8 Oxide Composition of Coal Tailings (XRF) Oxide Weight % (avg. of2 samples) SiO₂ 52.48 Al₂O₃ 21.76 Fe₂O₃ 15.74 MgO 1.29 CaO 1.57 Na₂O0.28 K₂O 3.08

Dried coal tailings with measured D[3,2] of 9.9 μm were fed through avitrification apparatus that combusted excess coal and heated theinorganic material through a liquid phase change to approximately 1450°C., followed by a rapid quenching step. The coal fraction in thefeedstock added considerable energy to the process: the flame powerincreased at least 46% processing coal tailings compared to an “inert”basalt processed at the same mass flow rate.

Successful melting through the liquid phase was demonstrated forinorganic particles by a highly spherical bulk particle morphology, withmean roundness (R)>0.8, and D[3,2] equal to 11.2 μm.

The microspheroidal coal tailings reagent powder has a molar Si/(Al,Fe³⁺) of 5.66, and molar cementitious reagent formula of(Ca,Mg)_(0.38).(Na,K)_(0.10).(Al, Fe³⁺)₁.Si_(5.66) and CaO of 1.7 wt. %(CaO,MgO of 2.56%).

A 45 g mixture is made containing 0.57 moles of water, 0.04 molesNa₂O+K₂O, 0.42 moles SiO₂ and 0.12 moles Al₂O₃+Fe₂O₃. The source ofAl₂O₃+Fe₂O₃ is the coal tailings microspheroidal powder prepared above.The source of SiO₂ is also the coal tailings powder and sodium silicate.The source of sodium oxide is sodium silicate and sodium hydroxide. Theoxide mole ratios are provided in Table 9, shown below.

TABLE 9 Oxide mole ratios (Na₂O, K₂O)/SiO₂ 0.11 SiO₂/(Al₂O₃, Fe₂O₃) 4.45H₂O/(Al₂O₃, Fe₂O₃) 4.85 (Na₂O, K₂O)/(Al₂O₃, Fe₂O₃) 0.49 H₂O/(Na₂O, K₂O)14.25

The mixture was cast into a cube mold, followed by 6 hours of sealedcuring at 80 degrees Celsius. The sample was demolded and found to havea compressive strength of 21 MPa and a glossy ceramic-like surface.

Example 5: Dredged Sediment

A sediment sample was acquired from the middle of Vancouver Harbour, BCto represent an example of dredged sediment. The sample has the oxidecomposition provided in Table 10, shown below.

TABLE 10 Oxide Composition of sediment (XRF) Oxide Weight % SiO₂ 67.06Al₂O₃ 12.69 Fe₂O₃ 5.62 MgO 2.4 CaO 2.98 Na₂O 2.69 K₂O 1.64

The sample was dried and found to have a mass median diameter, D50, of47 μm. Next, the sample was sieved to remove particles not passing 75μm.

This powder was fed through a vitrification apparatus that heated thematerial through a liquid phase change to approximately 1450° C.,followed by a rapid quenching step.

Successful melting through the liquid phase was demonstrated for mostparticles by a highly spherical bulk particle morphology. Themicrospheroidal sediment reagent powder has a molar Si/(Al, Fe³⁺) of11.49, and molar cementitious reagent formula of(Ca,Mg)_(1.55).(Na,K)_(0.51).(Al, Fe³⁺)₁.Si_(11.49) and CaO of 4.42 wt.% (CaO,MgO of 7.14%).

Individual particles are highly spherical and smooth, with meanroundness (R)>0.8, and D[3,2] of 11.8 μm.

A 98 g mixture is made containing 0.89 moles of water, 0.09 molesNa₂O+K₂O, 0.8 moles SiO₂ and 0.13 moles Al₂O₃+Fe₂O₃. The source ofAl₂O₃+Fe₂O₃ is the microspheroidal sediment powder prepared above. Thesource of SiO₂ is also the sediment powder and potassium silicate. Thesource of potassium oxide is potassium silicate and potassium hydroxide.The oxide mole ratios are provided in Table 11.

TABLE 11 Oxide mole ratios (Na₂O, K₂O)/SiO₂ 0.12 SiO₂/(Al₂O₃, Fe₂O₃)6.15 H₂O/(Al₂O₃, Fe₂O₃) 6.85 (Na₂O, K₂O)/(Al₂O₃, Fe₂O₃) 0.69 H₂O/(Na₂O,K₂O) 9.19

110 g of sand was added to the mixture, and the sample was cast into acube mold, followed by 6 hours of sealed curing at 80 degrees Celsius.The compressive strength of the mortar cube was determined to be 25 MPa.

Example 6: Copper Mine Tailings

A sample of copper porphyry flotation tailings was acquired fromArgentina to represent an example of a globally abundant aluminosilicatewaste material. The sample has the oxide composition provided in Table12, shown below.

TABLE 12 Oxide Composition of sediment (XRF) Oxide Weight % SiO₂ 70.98Al₂O₃ 15.26 Fe₂O₃ 2.64 MgO 1.18 CaO 1.09 Na₂O 2.75 K₂O 3.44

The sample was sieved to remove particles not passing 75 μm. This powderwas fed through a vitrification apparatus that heated the materialthrough a liquid phase change to approximately 1450° C., followed by arapid quenching step. Successful melting through the liquid phase wasdemonstrated for most particles by a highly spherical bulk particlemorphology.

The microspheroidal mine tailings reagent powder has a molar Si/(Al,Fe³⁺) of 14.2, and molar cementitious reagent formula of(Ca,Mg)_(0.6).(Na,K)_(0.5).(Al, Fe³⁺)₁.Si_(14.2) and CaO of 1.94 wt. %(CaO,MgO of 4.87%).

Individual particles are highly spherical and smooth, mean roundness (R)is greater than 0.8, and D[3,2] is 11.4 μm.

A 103.6 g mixture is made containing 0.76 moles of water, 0.11 molesNa₂O+K₂O, 1.04 moles SiO₂ and 0.13 moles Al₂O₃+Fe₂O₃. The source ofAl₂O₃+Fe₂O₃ is the microspheroidal tailings powder prepared above. Thesource of SiO₂ is also the tailings powder and potassium silicate. Thesource of potassium oxide is potassium silicate and potassium hydroxide.The oxide mole ratios are provided in Table 13, shown below.

TABLE 13 Oxide mole ratios (Na₂O, K₂O)/SiO₂ 0.10 SiO₂/(Al₂O₃, Fe₂O₃)8.64 H₂O/(Al₂O₃, Fe₂O₃) 7.78 (Na₂O, K₂O)/(Al₂O₃, Fe₂O₃) 0.89 H₂O/(Na₂O,K₂O) 9.67

110 g of sand was added to the mixture, and the sample was cast into acube mold, followed by 6 hours of sealed curing at 80 degrees Celsius.The compressive strength of the mortar cube was determined to be 18 MPa.

Example 7: Waste Concrete

Structural concrete cores were sampled from a mid-rise condominiumconstruction site in Vancouver, BC. The material has the oxidecomposition provided in Table 14, shown below.

TABLE 14 Oxide Composition of a Structural Concrete (XRF) Oxide Weight %SiO₂ 56.61 Al₂O₃ 13.94 Fe₂O₃ 5.15 MgO 1.42 CaO 12.55 Na₂O 3.55 K₂O 1.48

The sample was sieved to remove particles not passing 75 μm. This powderwas fed through a vitrification apparatus that heated the materialthrough a liquid phase change to approximately 1450° C., followed by arapid quenching step.

Successful melting through the liquid phase was demonstrated for mostparticles by a highly spherical bulk particle morphology.

The microspheroidal concrete reagent powder has a molar Si/(Al, Fe³⁺) of12.3, and molar cementitious reagent formula of(Ca,Mg)_(3.06).(Na,K)_(0.7).(Al, Fe³⁺)₁.Si_(12.3) and CaO of 12.55 wt. %(CaO,MgO of 13.97%).

Individual particles are highly spherical and smooth, mean roundness (R)is greater than 0.8, and D[3,2] is 10.0 μm.

A 100 g mixture is made containing 1.27 moles of water, 0.08 molesNa₂O+K₂O, 0.73 moles SiO₂ and 0.13 moles Al₂O₃+Fe₂O₃. The source ofAl₂O₃+Fe₂O₃ is the microspheroidal concrete powder prepared above. Thesource of SiO₂ is also the concrete powder and potassium silicate. Thesource of potassium oxide is potassium silicate and potassium hydroxide.The oxide mole ratios are provided in Table 15, shown below.

TABLE 15 Oxide mole ratios (Na₂O, K₂O)/SiO₂ 0.11 SiO₂/(Al₂O₃, Fe₂O₃)7.59 H₂O/(Al₂O₃, Fe₂O₃) 10.79 (Na₂O, K₂O)/(Al₂O₃, Fe₂O₃) 0.86 H₂O/(Na₂O,K₂O) 15.46

100 g of sand was added to the mixture, and the sample was cast into acube mold, followed by 6 hours of sealed curing at 80 degrees Celsius.The compressive strength of the mortar cube was determined to be 27 MPa.

Example 8: Quarried Aggregate

Granodioritic crusher dust from an aggregate quarry near Vancouver,Canada was sampled for the following experiment. The sample has an oxidecomposition (SEM-EDX) of approximately SiO₂-73%; Al₂O₃-15%, Fe₂O₃₋₃%;MgO-0%; CaO-2%; Na₂O-3%; K₂O-4%. The rock was further crushed and milledto a fine powder completely passing 75 μm.

The resulting powder was processed by an in-flight vitrificationapparatus that heated the material through a liquid phase change toapproximately 1450° C., followed by a rapid quenching step.

Successful melting through the liquid phase was demonstrated for mostparticles by a highly smooth and spherical bulk particle morphology.

Individual particles are highly spherical and smooth, mean roundness (R)is greater than 0.8, and D[3,2] is 9.3 μm. The microspheroidalgranodiorite glass reagent powder has a molar Si/(Al, Fe³⁺) of 16.0, andmolar cementitious reagent formula of (Ca,Mg)_(2.5).(Na,K)_(4.4).(Al,Fe³⁺)₁.Si_(16.0) and CaO of 2 wt. % (CaO,MgO of 2%).

A 105 g mixture is made containing 1.53 moles of water, 0.1 molesNa₂O+K₂O, 0.93 moles SiO₂ and 0.12 moles Al₂O₃+Fe₂O₃. The source ofAl₂O₃+Fe₂O₃ is the microspheroidal aggregate powder prepared above. Thesource of SiO₂ is also the aggregate powder and potassium silicate. Thesource of potassium oxide is potassium silicate and potassium hydroxide.The oxide mole ratios are provided in Table 16.

TABLE 16 Oxide mole ratios (Na₂O, K₂O)/SiO₂ 0.1 SiO₂/(Al₂O₃, Fe₂O₃) 8.0H₂O/(Al₂O₃, Fe₂O₃) 10.8 (Na₂O, K₂O)/(Al₂O₃, Fe₂O₃) 0.9 H₂O/(Na₂O, K₂O)12.9

The mixture above was cast as a paste into a cube mold, followed by 24hours of sealed curing at 80 degrees Celsius. The compressive strengthof the paste cube was determined to be 11 MPa, showing that the materialgains strength with heat curing, as expected. The lower relativestrength can be explained by the omission of sand (as in mortar), andhigher unmolten quartz mineral content compared to other examples(quartz melts at >1600° C.), which acts as a relatively inert filler.

Summary of Examples 1 to 8

Table 17 summarizes the main findings of Examples 1-8 and also providesa comparison against the performance of two fly ashes; one commerciallyavailable Type F fly ash that has been beneficiated (B-FA), and fly ashof Type F composition sampled directly from a coal power plant in NovaScotia, Canada. A visual representation of the roundness R distributionsis provided in FIG. 5.

TABLE 17 Summary of Examples 1 to 8 Mortar Particle Size CompressiveD[3, 2] R (Roundness) Strength Example Sample Material Type (μm) MeanStDev n (MPa) 1 PUM-1 Pumice Feedstock 0.79 0.21 201 <1 Processed 11.00.86 0.11 128 11 2 B-FC Basalt Feedstock 0.80 0.15 151 Processed 10.50.89 0.10 160 19 3 BD-1 Basalt Feedstock 0.75 0.16 1326 Processed 8.00.91 0.08 230 27 4 VJ Coal Tailings Feedstock 0.73 0.17 561 Processed11.2 0.89 0.06 652 21 5 FRS Sediment Feedstock 0.79 0.66 2383 6 LA-01Copper Mine Feedstock 0.68 0.21 1414 Tailings Processed 11.4 0.90 0.08294 18 7 SC-01 Demolished Feedstock 0.78 0.14 627 Concrete Processed10.0 0.88 0.10 238 27 8 SV-AGG Felsic Feedstock 0.78 0.16 2564 AggregateProcessed 9.3 0.88 0.07 951 11 L-FA Fly Ash (Type F) Direct from 3.90.83 0.13 1505 2.2 Power Plant B-FA Fly Ash (Type F) Beneficiated 5.10.87 0.07 797 23 R—roundness (unitless), as defined by Takashimizu &Iiyoshi (2016), n—number of particles analyzed.

Example 9: Use of Synthetic Cementitious Reagent as Alternative SCM

Microspheroidal basalt sample “BD” of Example 3 above was furtherprocessed by pulverizing the powder in a ring mill for 5 minutes,causing the coarsest particles to break and thereby increase reactivesurface area. The D[3,2] particle size was determined to be 3.6 μm bylaser diffraction analysis. Interestingly, small spheres <10 μm tend toact as ball bearings in the mill and resist breakage. The reagent'sstrength activity index was compared to a commercially availablehigh-quality Type F fly ash with an oxide composition SiO₂-52.09%;Al₂O₃-18.58%, Fe₂O₃-4.25%; MgO-2.98%; CaO-10.25%; Na₂O-6.03%; K₂O-1.72%.

Following ASTM C618, 50 mm cubes were cast of a Portland cement controlmix, Portland cement with fly ash (20% and 40% replacement), andPortland cement with cementitious reagent BD powder (also 20% and 40%replacement). Table 18 provides the compressive strength results at 7and 28 days. The performance of the BD mix at 20% replacement wascomparable with the commercial Type F fly ash and the strength activityindex was acceptable. The BD mix was easily workable and mixed withouttrouble. Notably, both the BD reagent and fly ash produce very useablemortar strengths greater than 40 MPa after 28 days at 40% replacement ofPortland cement. BD cementitious reagent can therefore be considered asuitable fly ash replacement in terms of compressive strength.

TABLE 18 Strength of Portland cement with cementitious reagent BD powderStrength Activity Index Compressive Strength Ratio to control Ratio tocontrol 7 days 28 days (7 days) (28 days) Control 45.4 60.8 FA-20 38.648.4 85% 79% FA-40 29.2 42 BD-20 38.4 50.8 84% 83% BD-40 26.4 44 Minimumrequirement 75% 75% of ASTM C618

Cementitious Material

According to some embodiments, a novel method of production and uses ofcementitious reagents, geopolymer reagents and supplementarycementitious materials (SCM) provides significant advantages over theknown methods and formulas.

According to some embodiments, a cementitious reagent has the oxideFormula 1: (CaO,MgO)a.(Na₂O,K₂O)b.(Al₂O₃,Fe₂O₃)c.(SiO₂)d, where a isabout 0 to about 4, b is about 0.1 to about 1, c is 1, and d is about 1to about 15.

Advantageously, the cementitious reagent may be formulated from abundantrocks, minerals and compounds of suitable composition. Preferably theCaO content is lower that about 30 wt. % in order to reduce the CO₂impact of cement.

In some embodiments, the cementitious reagent is in the form of anon-crystalline solid. In embodiments, the cementitious reagent is in apowder form having a particle size distribution with a D50 (mediandiameter) of approximately 20 μm or less, or preferably 10 μm or less.

In embodiments, the cementitious reagent includes at least one of thefollowing properties: a content of 45%-100%, and preferably 90-100%,X-ray amorphous solid; and molar composition ratios of(Ca,Mg)₀₋₁₂.(Na,K)_(0.05-1).(Al, Fe³⁺)₁.Si₁₋₂₀.

In some embodiments, the cementitious reagent includes less than about10 wt. % CaO. In other embodiments, the cementitious reagent includesmore than about 30 wt. % CaO. The composition of cementitious reagentwith respect to molar ratio of (Na, K) and Ca may be varied to obtaincertain advantages depending on the binder. For example, a cementitiousreagent with less than about 10 wt. % CaO is suitable for use inheat-cured geopolymer and as a fly ash substitute. In the alternative, acementitious reagent with greater than about 30 wt. % CaO has hydraulicproperties and may be added to a geopolymer resin to allowambient-temperature curing of geopolymer cement and may directly replaceblast furnace slag in blended Portland cement.

In some embodiments, the cementitious reagent is a low-calciumcontaining cementitious reagent with a molar composition of Si/(Fe³⁺,Al)between 1-20, and with a CaO content of about 10 wt. % or less.Preferably such a cementitious reagent is 40-100% X-ray amorphous, morepreferably about 80 to about 100% X-ray amorphous, even more preferably100% non-crystalline. Such a low-calcium containing cementitious reagentmay find numerous commercial applications, for instance, as a pozzolanicadmixture in hydraulic cement, and/or as a reagent in geopolymer bindersand cements.

In other embodiments, the cementitious reagent is a high-calciumcontaining cementitious reagent with a molar composition of Si/(Fe³⁺,Al)between 1-20, and a CaO content of about 10 to about 50 wt. %,preferably about 20 to about 45 wt. %. Preferably such cementitiousreagent is 40-100% X-ray amorphous, more preferably about 80 to about100% X-ray amorphous, even more preferably 100% non-crystalline. Such ahigh-calcium containing cementitious reagent may find numerouscommercial applications, for instance as a hydraulic admixture inblended hydraulic cement and/or as a reagent in geopolymer binders andcements.

In still further embodiments, the cementitious reagent is anintermediate-calcium containing cementitious reagent with a molarcomposition of Si/(Fe³⁺,Al) between 1-20, and a CaO content of about 10to about 20 wt. %. Preferably such cementitious reagent is about 40 toabout 100% X-ray amorphous, more preferably about 80 to about 100% X-rayamorphous, and even more preferably 100% non-crystalline. Such anintermediate-calcium containing cementitious reagent may find numerouscommercial applications, for instance as a cementitious reagent withdesirable intermediate hydraulic and pozzolanic properties.

Advantages of selecting Na/K in the cementitious reagent in accordancewith certain embodiments may be realized in: 1) SCM applications wherefree lime in hydraulic cement will exchange with soluble alkalis andcoordinate with sialate molecules from the cementitious reagent tocreate relatively stable alkali aluminosilicate polymerization thatgreatly improves chemical properties of traditional hydraulic cements;and 2) the fact that geopolymer reagents with significant Na/K contentmay be implemented with less soluble silicate hardener, thus decreasingthe soluble silicate requirement (and cost) of a geopolymer mix design.

Methods of Preparation

In some embodiments, aluminosilicate materials are selected as afeedstock for producing cementitious reagent. FIG. 1 shows exemplarysteps that may be implemented to produce cementitious reagent fromaluminosilicate materials, in accordance with some embodiments.

Briefly, an aluminosilicate material 101 is selected, and its chemicalcomposition is analyzed 102 and evaluated. The feedstock may be analyzedby any suitable quantitative or semi-quantitative methods such as XRF,XRD with Rietveld Refinement, LIBS, EDS, wet chemical analysis, andvarious other existing methods to determine the feedstock elementalcomposition.

If the selected composition is not acceptable, the material is amended,blended (e.g., in a vessel prior to thermochemical processing), orsorted 103, for example, through addition of a composition adjustmentmaterial 104. As used herein, the term “composition adjustment material”refers to any solid or liquid material with a composition suitable forpreferentially altering the bulk composition of the aluminosilicatematerial 101 with respect to one or several of the elements Ca, Na, K,Al, Fe, and Si.

As described above, composition adjustment materials that introducecalcium (Ca) may be include CaCO₃, Ca(OH)₂, CaO, CaCl, calcium silicateminerals and compounds, calcium aluminum silicate minerals andcompounds, waste Portland cement products, wollastonite, gehlenite, andother melilite group mineral compositions.

As described above, composition adjustment materials that introducealuminum (Al) may include aluminous rocks, minerals, soils, sediments,by-products, and compounds including one or more of kaolinite,halloysite and other aluminum-rich/alkali-poor clay minerals, Al₂SiO₅polymorphs, chloritoid, staurolite, garnet, corundum, mullite,gehlenite, diaspore, boehmite, gibbsite, and nepheline and otherfeldspathoids. Other materials that may be used include aluminum metal,bauxite, alumina, red mud (alumina refinery residues).

As described above, composition adjustment materials that introduce iron(Fe) may include iron-rich rocks, minerals, soils, sediments,by-products, and compounds such as olivine, chlorite minerals(chamosite, clinochlore, etc.), pyroxenes, amphiboles, goethite,hematite, magnetite, ferrihydrite, lepidicrocite and other ironoxy-hydroxide compositions, iron-rich clay and phyllosilicate minerals,and elemental iron.

Sorting 105 may also be used as a composition adjustment method 103 andany undesirable waste material may be discarded.

The resulting solid aluminosilicate material having a desirablecomposition is next heated 106. The heating is carried out to reach aheating temperature above a liquid phase temperature to obtain a liquid,for instance about 1000° C. to about 1600° C., or about 1300° C. toabout 1550° C. Any suitable method or apparatus may be used for theheating and for obtaining the liquid including, but not limited to,in-flight melting and/or batch melting. This may be achieved by using,for instance, a plasma furnace, an oxy-fuel furnace, an arc furnace, areverberatory furnace, a rotary kiln and/or a solar furnace. Typically,a furnace temperature of about 1000° C. to about 1600° C. is needed, andmost typically about 1300° C. to about 1550° C. to obtain the desiredliquid phase.

If desired, a fluxing material may be added to the solid aluminosilicatematerial to lower its melting point and/or to induce depolymerization ofthe liquid. The fluxing material may be mixed with the solidaluminosilicate material prior to heating or during the heating. Commonfluxing materials that may induce depolymerization in melts, and/orlower melting temperature include CaF₂, CaCO₃, waste glass, glasscullet, glass frit, alkali-bearing minerals (e.g., feldspars, zeolites,clays, and feldspathoid minerals), borate salts, halogen compounds(fluoride and chloride bearing salts) and calcium salts.

Next, the aluminosilicate liquid (e.g., molten particles) is quenched107 to obtain a solid. In embodiments, the quenching step includesreducing temperature of the liquid significantly below the glasstransition temperature, for instance at 500° C. or lower, or preferablybelow 200° C. or lower. In embodiments, the quenching is done rapidly,i.e., the temperature is reduced at a rate of about 10² Ks⁻¹-10⁶ Ks⁻¹(preferably at a rate of >10³⁵ Ks⁻¹). Any suitable method may be usedfor the quenching including, but not limited to, contacting the moltenmaterial with a sufficient stream of adequately cool air, steam, orwater to produce a non-crystalline solid.

Next, the solid is crushed and/or pulverized in order to reduce particlesize 108 and obtain the cementitious reagent 109. This may be carriedout using any suitable method or apparatus including, but not limitedto, a ball mill, a roller mill and a vertical roller mill. Preferablythe particle size is reduced to obtain a fine powder useful incementitious applications. In embodiments, the powder has a particlesize distribution with D50 (median diameter) of approximately 20 μm orless, more preferably 10 μm or less. Such a particle size is generallydesirable to ensure sufficient reactivity and consistent materialproperties.

Uses of the Cementitious Reagent

One related aspect concerns the broad relevance of the cementitiousreagent described herein. Appropriate compositions of engineeredcementitious reagent may be used interchangeably in significantproportion in both geopolymer cements and hydraulic cements (i.e.,cements that react with water).

Accordingly, embodiments described herein encompass geopolymer cementsand hydraulic cements including at least 5 wt. %, or at least 10 wt. %,or at least 15 wt. %, or at least 20 wt. %, or at least 25 wt. %, or atleast 30 wt. %, or at least 40 wt. %, or at least 50 wt. %, or at least60 wt. %, or at least 70 wt. %, or at least 80 wt. %, or at least 90 wt.%, or more, of a cementitious reagent as described herein.

In accordance with another aspect, some embodiments relate to asupplementary cementitious material (SCM) including a cementitiousreagent as defined herein. In embodiments, the SCM includes about 5 wt.% to about 50 wt. % (preferably at least 20 wt. %) of the cementitiousreagent as defined herein.

In accordance with another aspect, some embodiments relate to asupplementary cementitious material (SCM) having one or more of thefollowing properties: includes less than about 35 wt. % CaO, withappreciable content of Na/K (e.g., at least 2 wt. %, preferably at least5 wt. %) and Al content (e.g., at least 5 wt. %) and is in the form of anon-crystalline solid.

In accordance with another aspect, some embodiments relate to a solidconcrete, including a cementitious reagent as described herein, i.e.,including about 5 wt. % to about 50 wt. % (preferably at least 20 wt. %)of the cementitious reagent as described herein.

In accordance with another aspect, some embodiments relate to a blendedhydraulic cement that is distinguishable from Portland cement. Forinstance, solid-state ²⁹Si NMR spectroscopy can differentiate blendedhydraulic cement with low iron (<5 wt. %) from Portland cement (havingdominant CSH binder constituent) by the amount and type of connectivityof silica tetrahedra in the cured cements. Indeed, cured Portland cementbinder phases are characterized by low coordination and hydrated sites(Q1, Q1(OH), Q2, and Q2(OH)), insignificant tetrahedral Al substitution,and no higher coordination (i.e., no Q3 and Q4 sites).

The blended hydraulic cement with cementitious reagent may show thetypical CSH-related sites above in addition to unique features such as:aluminum substitution (e.g., Q2(1 Al)), and a “higher” level ofcoordination than Portland cement (i.e., branching). For instance, ablended hydraulic cement can include at least a Q3 level of coordination(e.g., (Q3(2 Al), Q3(1 Al), Q3(0 Al)). In embodiments the blendedhydraulic cement contains a measurable proportion (>1 wt. %) ofthree-dimensional cross-linking (Q4 sites) which is not known inconventional hydraulic cements. In accordance with another aspect,disclosed is a geopolymer binder including a cementitious reagent asdefined as defined herein, i.e., including about 5 wt. % to about 90 wt.% (preferably at least 20 wt. %, at least 30 wt. %, at least 50 wt. %,at least 75 wt. %,) of the cementitious reagent as defined herein.

In accordance with another aspect, some embodiments relate to solidgeopolymer concrete including about 5 wt. % to about 50 wt. %(preferably at least 20 wt. %) of the cementitious reagent as definedherein.

Those skilled in the art can appreciate that the present disclosureadvantageously provides methods to produce versatile low-CO₂cementitious reagents from abundant, cheap natural materials. Anothersignificant advantage is the creation of a single reagent that meetsspecification standards for alternative SCMs, while also meeting theneeds of the growing geopolymer market.

Aluminosilicate Materials

As described herein, some embodiments provide a method forthermochemical processing of aluminosilicate materials to produce asolid cementitious reagent that may advantageously be used as analternative supplementary cementitious material (SCM) in blendedhydraulic cement and/or as a geopolymer solid reagent in geopolymerbinders (thus eliminating the need for some or all of MK-750, fly ash,GGBFS, and other common solid reagents).

In some cases, an aluminosilicate material is used to produce anon-crystalline cementitious reagent. In some embodiments, analuminosilicate material is used to produce at least one of asupplementary cementitious material (SCM) and a geopolymer reagent. Insome embodiments, the aluminosilicate material is selected from dredgedsediments, demolished concrete, mine wastes, glacial clay, glacialdeposits, fluvial deposits, rocks and mineral mixtures, for instancerocks and mineral mixtures composed of some or all the elements Ca, Na,K, Fe, Al and Si. In some embodiments, aluminosilicate materials areselected as a feedstock for producing cementitious reagent. Thefeedstock may be analyzed by quantitative or semi-quantitative methodssuch as XRF, XRD with Rietveld Refinement, LIBS, EDS, wet chemicalanalysis, and various other existing methods to determine the feedstockelemental composition.

Example 10: Using Dredged Sediments

A sample of sediments was taken from the tidal lower reaches of theFraser River, Vancouver, BC. The sample is composed of fine sand, siltand clay size fractions. The mineralogy of the sample is given in Table19 (determined by XRD with Rietveld refinement) and the oxidecomposition of the major elements was estimated from the mineralogy(Table 20).

TABLE 19 Mineralogy of Fraser River Sediment Sample Phase Weight %quartz-low 42 andesine 16 albite-low 13 illite/muscovite 11 clinochlore5 augite 4 orthoclase 4 actinolite 4 dolomite 2 kaolinite 2

TABLE 20 Oxide Composition (estimated from mineralogy) Oxide Weight %SiO₂ 73.0 Al₂O₃ 11.9 Fe₂O₃ 0.2 FeO 1.5 MnO 0.0 MgO 3.1 CaO 3.3 Na₂O 2.6K₂O 1.4 CO₂ 0.9 H₂O 2.2

Fraser river sediment (FRS) was dried, classified, and the fractionpassing 120 μm was fed to a vitrification apparatus that heated thematerial through the melting point to approximately 1450° C., followedby a quenching step to cool the powder. The resulting FRS-glass powderwas ground in a ball mill to D50<20 μm. The X-ray amorphous component ofthe obtained powder was 52%. The mineralogy results yield an estimatedmolar Si/(Al, Fe³⁺) of 11.46, and molar cementitious reagent compositionof (Ca,Mg)_(1.25).(Na,K)_(0.34).(Al, Fe³⁺)₁-Si_(11.46) and CaO of 3.3wt. %. This may be qualified as a “low-Ca cementitious reagent.”

Heat-cured geopolymer binder: 5 parts of the low-Ca cementitious reagentwas mixed with 1 part potassium silicate solution (Molar ratioSiO₂:K₂O=1.45). The paste was mixed thoroughly, placed in a sealed moldand cured at 80° C. for 4 hours. The resulting hardened paste achievesat least 20 MPa compressive strength in a cylinder compression test.

Ambient-cured geopolymer binder: 5 parts of the low-Ca cementitiousreagent was mixed with 1 part potassium silicate solution (Molar ratioSiO₂:K₂O=1.45), 1 part water, and 1.5 parts finely ground CaSiO₃. Thesilicate solution was mixed with the CaSiO₃ powder and allowed to reactfor 15 minutes. The resulting paste was mixed thoroughly with the FRSglass powder and water, then placed in a sealed mold and cured at 20° C.for 7 days. The resulting hardened paste achieves at least 20 MPacompressive strength in a cylinder compression test.

Ambient-cured SCM application in Portland Cement: a series of Portlandcement mortar cubes were cast from a 50:50 mix of cement and sand. Thelow-Ca cementitious reagent was substituted at 0%, 20%, 40%, 60% and 80%in place of Portland cement in the mortar mix. The cubes were cured for7 days at 100% humidity and the compressive strength of the cubes ispresented in Table 21. Up to 60% replacement of ordinary Portland cement(“OPC”) yields useable compressive strength for many applications whileproportionally reducing CO₂ footprint of the mortar.

TABLE 21 7-Day Compressive Strength, SCM Application FRS CementitiousReagent (%) Compressive Strength (MPa ± 10)   0% (100% OPC) 40 20% (80%OPC) 37.5 40% (60% OPC) 30 60% (40% OPC) 15 80% (20% OPC) 3.5

Example 11: Using Demolished Concrete

A core of structural concrete was sampled from a 2019 mid-rise housingdevelopment in Vancouver, BC. The mineral composition of the concrete(including fine and coarse aggregate) is given in Table 22 (XRD withRietveld refinement), and the bulk elemental composition is calculatedfrom the mineralogy in Table 23.

TABLE 22 Mineralogy of concrete sample Phase Weight % albite-low(calcian) 31 quartz-low 21 albite-low 11 orthoclase 8 calcite 8 CSH gel6 clinozoisite 3 actinolite 3 clinochlore II 3 biotite 1M 2 ettringite 2C2S beta 2 brownmillerite (Al) 1 gypsum 1

TABLE 23 Oxide Composition (estimated from mineralogy) Oxide Weight %SiO₂ 64 Al₂O₃ 13 Fe₂O₃ 0 FeO 1 MnO 0 MgO 2 CaO 11 Na₂O 5 K₂O 2 CO₂ 4 H₂O4

The concrete was crushed and pulverized to a powder with D50 of about 20μm. The powder was fed through a vitrification apparatus that heated thematerial through the melting point to approximately 1450° C., followedby a quenching step. The resulting glassy particles were finely groundto a powder with D50 of approximately 5-15 μm.

The mineralogy results of this powder yield an estimated molar ratioSi/(Al, Fe³⁺) of 9.88, and a molar cementitious reagent composition of(Ca,Mg)_(2.79).(Na,K)_(0.55).(Al, Fe³⁺)₁.Si_(9.88) and CaO of 11 wt. %.This may be qualified as an “intermediate-Ca cementitious reagent.”

Ambient-cured geopolymer cement: Cement paste was thoroughly mixed byweight using the powdered concrete glass (2.5 parts), a potassiumsilicate solution with molar ratio SiO₂:K₂O=1.45 (0.74 parts), and water(0.08 parts). The paste was then placed in cylinder molds and cured at20° C. Setting time was estimated by Vicat needle penetration test.Initial setting occurred at 51 minutes, and final setting time was 195minutes.

Compressive strength of a mortar mix including 50:50 of theambient-cured geopolymer cement and sand was measured by compressingcylinders to failure. After 3 days, compressive strength attainedapproximately 25 MPa, and tensile strength was approximately 2 MPa (bysplit cylinder method).

To test high heat performance, a sample of the original structuralconcrete and a 1 cm diameter cast cylinder of geopolymer were subjectedto 750° C. in air for 2 hours. The Portland cement concrete decrepitatedand turned to powder upon handling, but the geopolymer mortar cylinderremained intact with no visible cracks or defects.

The novel methods, systems, apparatus, and formulations presented hereinprovide numerous benefits as detailed throughout. In some instances, thenovel formulation and processes result in a particle, powder, or reagentthat is particularly useful as a replacement for traditionalcementitious additives in hydraulic cement or geopolymer cementcompositions. The novel formulation may have a molar composition, inwhich:

$\frac{Si}{{Si} + {Al} + {Fe} + \left( {{Ca} + {Mg}} \right) + \left( {{Na} + K} \right)} = {{about}\mspace{14mu} 0.295\mspace{14mu}{to}\mspace{14mu}{about}\mspace{14mu} 0.605}$$\frac{Al}{{Si} + {Al} + {Fe} + \left( {{Ca} + {Mg}} \right) + \left( {{Na} + K} \right)} = {{about}\mspace{14mu} 0.190\mspace{14mu}{to}\mspace{14mu}{about}\mspace{14mu} 0.340}$$\frac{Fe}{{Si} + {Al} + {Fe} + \left( {{Ca} + {Mg}} \right) + \left( {{Na} + K} \right)} = {0\mspace{14mu}{to}\mspace{14mu}{about}\mspace{14mu} 0.16}$${\frac{{Ca} + {Mg}}{{Si} + {Al} + {Fe} + \left( {{Ca} + {Mg}} \right) + \left( {{Na} + K} \right)} = {0\mspace{14mu}{to}\mspace{14mu}{about}\mspace{14mu} 0.215}},{and}$$\frac{{Na} + K}{{Si} + {Al} + {Fe} + \left( {{Ca} + {Mg}} \right) + \left( {{Na} + K} \right)} = {{about}\mspace{14mu} 0.04\mspace{14mu}{to}\mspace{14mu}{about}\mspace{14mu} 0.24}$

While the novel compositions presented herein result in a uniquematerial that is especially suited for the purposes describedthroughout, it can be difficult to differentiate the material by itsindividual elemental ranges or a region on a ternary diagram alone, dueto the fact that ternary diagrams are limited to visualization ofexactly three compositional parts and all the elemental parts of thetotal composition have interdependent relationships.

As geochemical compositions are classified as “compositional data,” atransformation (centered log-ratio transformation—CLR) from the Simplexto the Euclidean space was applied to the 7-part compositions,preserving the information encoded in molar compositions in a way thatstandard statistical methods can handle.

On the CLR representation of chemical data, a Random Forestclassification was completed, and from this predictive model, the 8-ruleclassification set (presented below) was extracted. Using this rule set,fly ash and the described feedstock compositions are separated, despitethe fact that there may appear to be compositional overlap between thesematerials on ternary diagrams. A classification model such as this isuseful to accurately represent or classify compositions exceeding3-dimensional data.

Modeling the Novel Formulation and Material

The described glassy reagent (“Novel Feedstock” or alternativecementitious material “ACM”) is differentiated from fly ash in severalimportant characteristics, such as time-temperature history,manufacturability at nearly any location, and relatively lower values ofproblematic heavy metal contaminants. Major element chemical compositionof embodiments described herein is also readily differentiatedstatistically from fly ash using compositional rules. By way of example,a statistical model was built using fly ash compositional data from theliterature and expected suitable feedstock compositions as describedherein. The classification rules were generated from a subsample astraining data, and tested on remaining compositions (fly ash, and thenovel compositions described herein) to assess accuracy and predictivepower of the classification rules.

In the model below, fly ash is predicted correctly 94% of the time on331 global compositions of fly ash from the literature, and the other 6%were classified as “outside the rule set.” No fly ash samples weremisclassified as the novel feedstock geological material describedherein. The model was applied to more than 70,000 compositions ofnatural geological materials that fit in the disclosed molar compositionrange, and the model predicts the novel feedstock described herein with99% success rate. Less than 1% of the compositions fell under thecategory of “outside the rule set.” Clearly there are significant andpredictable differences between the novel feedstocks described hereinand other by product reagents, such as fly ash. Composition alone,represented in centered log-ratio coordinates (CLR) is highly accuratein discerning the chemistry of the described glassy particles from flyash.

Application of the Model

To apply the model below:

-   -   1. Measure bulk chemical composition of a given glassy sample by        any suitable analytical method and provide molar % of Si, Al,        Fe, Ca, Mg, Na and K.    -   2. Convert molar data to CLR coordinates for the 7 elements.    -   3. Apply the following conditions sequentially to predict        whether the sample is Fly Ash, or a Novel Feedstock material,        respectively.

Note: If a condition is not satisfied, apply next condition. If noconditions apply to given composition, ELSE predicts that the sample isoutside of the model's rule set and cannot be confidently predicted.

Rules

-   -   1. For glassy material with bulk CaO oxide equivalent wt. %<35%,        AND    -   2. Bulk mol % ratio Si/Al>2,

Notably, Rule 1 above can be used to rule out slag as a feedstock, andRule 2 can be used to rule out metakaolin, kaolinite, and other 1:1 clayrich feedstocks. Apply the following conditions to closed, CLRtransformed molar sample compositions using the logic IF(condition=TRUE), THEN (prediction), ELSE (move to next condition) asshown in Table 24 below:

TABLE 24 Condition Prediction Si > 0.40109 & Si < = 1.18718 & Al < =0.52677 & Al < = Novel 0.40675 & Ca < = −0.40656 & Ca < = −0.7324Feedstock Al > 0.5364 & Al > 0.55929 & Ca > −4.65173 & Na < = Fly Ash−1.2763 & Mg < = −0.7076 & K > −4.1446 Si > 0.43721 & Fe < = 0.31807 &Fe > −2.32162 & Ca < = Novel −0.08759 & Mg > −1.80049 & Mg > −1.47036Feedstock Al < = 0.52677 & Ca < = −0.31475 & K > −1.52367 NovelFeedstock Si < = 0.44413 & K < = −2.12091 Fly Ash Fe > −1.19597 & Ca < =−0.36227 & Na > −1.79741 & Na < = −0.18124 & Novel Mg > −2.7976 & K < =−1.87031 Feedstock Al > 0.5364 & Fe > −2.59819 & Mg < = −0.7076 & Mg >Fly Ash −6.29972 & Mg < = −0.93309 & K > −4.10525 ELSE Outside rule set

FIG. 11 illustrates the region of the novel 7-part molar compositions ina complete set of ternary diagrams. The circled areas highlight thedifferences between the Novel Feedstock and global fly ash samples fromthe literature. Examples As illustrated, the top row of four ternarydiagrams represents the Si perspective and is shown in more detail inFIG. 12. With reference to FIGS. 11-15, a black outline of samplesindicates the alternative cementitious material (“ACM”) describedherein, which may also be referred to as the Novel Feedstock. ACMCompositions of Examples 1-8 are shown as black dots labelled with thenumber corresponding to the example composition (numbers andcompositions summarized in Table 17). The grey outline shown in thefigures represents a 90% confidence interval of fly ash samples, basedon 331 unique samples (same as were categorized using the abovestatistical model).

The second row of figures in FIG. 11 represents ternary diagrams fromthe Al perspective and is shown in further detail in FIG. 13. The thirdrow of figures in FIG. 11 represents ternary diagrams from the Feperspective and is shown in further detail in FIG. 14. Finally, the lastrow of FIG. 11 represents a ternary diagram from the Ca+Mg perspectiveand is shown in greater detail in FIG. 15.

FIGS. 11-15 illustrate the Novel Feedstock as it relates to global flyash compositions and clearly shows that the two material populations arehighly distinguishable from each other even on elemental molar ternarydiagrams. The areas of apparent overlap between the Novel Feedstock andfly ash are shown to be differentiated in the higher dimensionalclassification model provided herein. The Novel Feedstocks or ACMdescribed herein are not particularly alkali resistant and participatein a reaction with alkali hydroxides or lime as a reagent.

Blended Cementitious Material

Supplementary cementitious materials (SCMs) may be added to OrdinaryPortland Cement (OPC), for example, to form concrete having improvedperformance. In particular, some SCMs undergo pozzolanic reactionsconsuming calcium hydroxide in the matrix to produce a C—S—H gel thatmay beneficially impact strength, durability and resistance to alkalisilica reaction. In a similar vein, SCMs having a microspheroidalmorphology may improve the workability of concrete and accordinglydecrease water demand. In addition, as a micro-aggregate, SCMs mayincrease the density of the concrete matrix. Furthermore, as a low CO₂addition that may consume less energy in production than Portlandcement, SCMs may decrease the carbon footprint associated with concreteproduction.

However, the implementation of conventional SCMs may be limited (e.g.,to about 15-25% of the total cementitious material in concrete) due totheir adverse effect on the development of early strength. In view ofthe foregoing, disclosed is a blended cement having an elevated SCMcontent while also exhibiting desirable early strength gains.

In accordance with various embodiments, a blended cement (binder) mayinclude a mixture of (a) Portland cement (e.g., OPC), (b) fly ash (FA)and/or a microspheroidal glassy particle-based cementitious reagent(CR), as disclosed herein, (c) an alkali activator, and (d) analuminum-containing reagent, such as metakaolin. Such a blended cementmay be incorporated into a mixture for forming concrete.

Fly ash may include Class F fly ash, for example, although additionalcompositions may be used. Example alkali activators include anhydroussodium sulfate, sodium sulfate decahydrate (Glauber's salt), andpotassium sulfate, although further alkali sulfates are contemplated.

Constituents of the blended cement may be intermixed using any suitablemethod. For instance, the blended cement may be manufactured byinter-grinding hydraulic cement clinkers (e.g., alite-containingclinkers) with fly ash or a microspheroidal glassy particle-basedcementitious reagent and an alkali sulfate, or by separatelymanufacturing a hydraulic cement (e.g., ASTM, Type I) and then combiningwith fly ash or a microspheroidal glassy particle-based cementitiousreagent and a suitable alkali sulfate at a later stage, such as whilebatching for a concrete mix.

In some embodiments, the alkali sulfate may be inter-ground and mixedwith fly ash or a microspheroidal glassy particle-based cementitiousreagent. In some embodiments, the alkali sulfate may be separatelyground into a powder and dry-mixed with the fly ash or a microspheroidalglassy particle-based cementitious reagent prior to forming a paste,mortar, or concrete. In still further embodiments, the alkali sulfatemay be ground into a powder and dissolved in mixing water prior tomaking paste, mortar, or concrete. The mixing water may be heated (e.g.,35-40° C.) to improve the solubility of the alkali sulfate.

Metakaolin may be added to the blended cement. The silica and aluminapresent in the metakaolin may beneficially react with calcium hydroxideand other nascent alkali hydroxides and alkali silicates formed insolution by reaction of calcium hydroxide with the alkali activator.Furthermore, metakaolin may provide a filler effect, accelerate OPChydration, and undergo pozzolanic reactions to enhance the performanceof pastes, mortars, and concrete.

Relative to the combined amount of Portland cement, fly ash and/ormicrospheroidal glassy particle-based cementitious reagent, andmetakaolin, example blended cements may include (a) about 20 wt. % toabout 60 wt. % Portland cement, (b) about 40 wt. % to about 80 wt. % flyash or microspheroidal glassy particle-based cementitious reagent, (c)up to about 7.5 wt. % alkali activator, and (d) up to about 10 wt. %metakaolin.

In certain embodiments, the blended cement may include 20, 30, 40, 50,60 wt. % or more Portland cement, including ranges between any of theforegoing values. In certain embodiments, the blended cement may include40, 45, 50, 55, 60, 65, 70, 75, or 80 wt. % fly ash or microspheroidalglassy particle-based cementitious reagent, including ranges between anyof the foregoing values. In certain embodiments, the blended cement mayinclude 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, or7.5 wt. % alkali activator, including ranges between any of theforegoing values. In certain embodiments, the blended cement may include0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 wt. % metakaolin, including rangesbetween any of the foregoing values.

Example 12: Setting Time

Blended cement mortars were made with a binder-to-sand ratio of 1.4 anda water-to-binder ratio of 0.36. Fly ash and a microspheroidal glassyparticle-based cementitious reagent were used as partial replacement forOPC. Compositions of example fly ash and cementitious reagent aresummarized in Table 25 and Table 26, respectively, whereas Table 27provides the composition of the metakaolin used herein, although the flyash, cementitious reagent, and metakaolin compositions are not strictlylimited.

TABLE 25 Composition of fly ash Oxide SiO₂ Al₂O₃ TiO₂ BaO Fe₂O₃ CaO MgOK₂O Na₂O SO₃ Content 52.09 18.58 0.7 0.66 4.25 10.25 2.98 1.72 6.03 0.61(wt. %)

The fly ash had a loss on ignition (LOI) of 0.3% at 1000° C. and isclassified as Class F (SiO₂+Al₂O₃+Fe₂O₃>70%) according to ASTM C618.

TABLE 26 Composition of Cementitious Reagent (Novel Formulation) OxideSiO₂ Al₂O₃ TiO₂ BaO Fe₂O₃ CaO MgO K₂O Na₂O SO₃ Content 58.37 13.85 0.580.06 7.85 5.61 3.21 2.87 2.68 0.17 (wt. %)

TABLE 27 Composition of Metakaolin Oxide SiO₂ Al₂O₃ TiO₂ BaO Fe₂O₃ CaOMgO K₂O Na₂O SO₃ Content 62.5 29.8 0.69 — 1.23 0.39 0.42 1.75 0.18 0.05(wt. %)

Portland cement, fly ash and/or cementitious reagent, and metakaolinwere initially dry mixed. Alkali sulfate was dissolved in mixing water,and the mixing water was then added to the dry binder materials andstirred for 1 minute. A water reducing admixture was added, followed bysand, and the combined mixture was stirred for 1-2 minutes to form amortar.

The mortar was poured into a Vicat mold. The setting times weredetermined according to ASTM C191-19. For determining the initialsetting time, periodic penetration tests using a 1 mm Vicat needle wereperformed on the mortar. The Vicat initial setting time is defined asthe time elapsed between the initial contact of cement and water and thetime when the penetration of the Vicat needle is 25 mm. The Vicat finalsetting time is defined as the time elapsed between the initial contactof cement and water and the time when the needle does not leave acircular impression on the mortar.

The results in Table 28 show that the addition of alkali sulfatedecreases the initial setting time by 83 minutes in the flyash-containing blended cement (Samples 1 and 3), and 92 minutes in thecementitious reagent-containing blended cement (Samples 2 and 4).

TABLE 28 Setting times for different blended cement trials SampleSetting time (minutes) no. Blended cement composition Initial Final 147.4% OPC + 47.4% fly ash + 155 209 5.2% metakaolin + 5% sodium sulfatedecahydrate 2 47.4% OPC + 47.4% CR + 141 232 5.2% metakaolin + 5% sodiumsulfate decahydrate 3 47.4% OPC + 47.4% fly ash + 238 >300 5.2%metakaolin + no activator 4 47.4% OPC + 47.4% CR + 233 >300 5.2%metakaolin + no activator

Example 13: Strength Development with Alkali Sulfate Content

A series of compressive strength tests were performed at various ages todemonstrate the performance of fly ash-containing blended cement mortarswith different amounts of alkali sulfate. Mortars were prepared with asand-to-binder ratio of 1.4 and a water-to-binder ratio of 0.36 asfollowed in the previous example. The strength tests were conducted on40 mm mortar cubes.

The results in Table 29 show that strength values over the 28 day testcycle increase with an increase in the amount of sodium sulfate up toabout 5%. However, at 7.5% sodium sulfate decahydrate, the overallstrength decreases relative to lesser amounts of activator.

TABLE 29 Strength development with alkali sulfate content Blended cementCompressive strength (MPa) Sample no. composition 1-day 3-day 7-day14-day 28-day 1 47.4% OPC + 47.4% 7.9 27.4 38.8 43.8 40 fly ash + 5.2%metakaolin + 1% sodium sulfate decahydrate 2 47.4% OPC + 47.4% 11 31.940.1 43.8 43.3 fly ash + 5.2% metakaolin + 2.5% sodium sulfatedecahydrate 3 47.4% OPC + 47.4% 12.5 35.3 43.8 43.6 47.5 fly ash + 5.2%metakaolin + 5% sodium sulfate decahydrate 4 47.4% OPC + 47.4% 10.3 36.839.3 38.3 46.2 fly ash + 5.2% metakaolin + 7.5% sodium sulfatedecahydrate 5 47.4% OPC + 47.4% 14.2 20 32 38.3 37.9 fly ash + 5.2%metakaolin + 5% potassium sulfate

Example 14: Strength Development with Percentage Replacement of OPC

A further series of compressive strength tests were performed at variousages to demonstrate the performance of cementitious reagent-basedblended cement mortars with different replacement amounts. Mortars wereprepared with a sand-to-binder ratio of 1.4 and a water-to-binder ratioof 0.36. The strength tests were conducted on 40 mm mortar cubes.

TABLE 30 Strength development with percent replacement Blended cementCompressive strength (MPa) Sample no. composition 1-day 3-day 7-day14-day 28-day 1 47.4% OPC + 21.8 21.1 34.2 41.6 40.8 47.4% CR + 5.2%metakaolin + 5% sodium sulfate decahydrate 2 47.4% OPC + 17 26 33.4 37.940.9 47.4% CR + 5.2% metakaolin + 5% potassium sulfate activator 3 47.4%OPC + 6.4 19.5 35.21 44.1 50 47.4% CR + 5.2% metakaolin + 0% activator 452.7% OPC + 20.7 31.2 42.6 47.3 46.6 42.1% CR + 5.2% metakaolin + 5%sodium sulfate decahydrate 5 42.1% OPC + 13.9 27.2 37.4 45.9 43.9 52.7%CR + 5.2% metakaolin + 5% sodium sulfate decahydrate 6 31.6% OPC + 10.623.8 34.9 39.5 44.2 63.2% CR + 5.2% metakaolin + 5% sodium sulfatedecahydrate 7 21.1% OPC + 5.8 16.9 23.1 27.3 28.2 73.7% CR + 5.2%metakaolin + 5% sodium sulfate decahydrate

The results in Table 30 show the performance of cementitious reagent-OPCcement blends at different replacement amounts. It is evident from theresults that the addition of alkali sulfates tremendously improve theearly age strength. For OPC amounts of 40% to 60%, the compressivestrength values meet the requirements of High Early strength (HE) typecement pursuant to ASTM C1157. The blended cements with 20%-60% OPC allmeet the minimum requirements of type GU cement pursuant to ASTM C1157.

FIG. 16 illustrates a schematic flow diagram of the process 1600 ofmaking an alternative cement concrete using a relatively smalldecentralized in-flight mini kiln. The mini kiln can be located at anysuitable place, and because of the size and nature of the mini kiln, isespecially suited to be collocated at an aggregate quarry, at a concretebatch plant, in between a quarry and a concrete batch plant, or anyother suitable location to minimize, or at least reduce, thetransportation time and distance typically required for concrete batchplants relying on Portland cement.

At 1602, an aluminosilicate aggregate is provided, as described herein.The aggregate material may be any suitable aluminosilicate material, andmay be specifically mined for the intended purpose, or may be wastematerial, such as mine tailings, ground concrete, or some other type ofaggregate. At block 1604, the aluminosilicate material is milled to apowder, as described herein.

At block 1606, a milled aluminosilicate material may be stored, shipped,or provided to an input of a mini kiln as described herein. At block1608, energy is added to the milled aluminosilicate aggregate, such ascombustion of an air/fuel mixture, a torch, industrial heat, or someother form of energy to increase the temperature of the aggregate. Insome embodiments, the aluminosilicate particles are optionally amended,blended (e.g., in a vessel prior to thermochemical processing), forexample, through addition of a composition adjustment material in orderto reach desired ratio(s) with respect to one or several of the elementsCa, Mg, Na, K, Al, Fe, and Si.

At block 1608, the energy causes the aluminosilicate aggregate to melt,which in some cases, occurs in-flight (at block 1610), such as where theaggregate is entrained within a column of air and/or air/fuel within amelting chamber.

At block 1612, after the aggregate is melted and quenched, the feedstockbecomes glassy aluminosilicate particles. In some cases, the particlesare substantially spheroidal with a roundness R>0.8.

At block 1614, the particles are combined with other ingredients at aconcrete batch mixing plant, which may be collocated with the mini kilnin some instances. At block 1616, Additives may be added to theconcrete, such as hardener, ambient cure reagent, admixtures,plasticizers, reinforcement materials, and the like. At block 1618, sandand coarse aggregate may be added to the cement as is known in the art.

At block 1620, the final concrete mixture is formed and ready to beused.

According to some embodiments, a method of cement production decreasescement transportation distance (and therefore cost) compared toconventional methods. Some embodiments allow for decentralizedproduction of an Alternative Cement Material (ACM) in close proximity toan aluminosilicate aggregate quarry and a concrete batch plant. This ACMmay be advantageously used as a primary reagent in a suitablealternative cement formulation that can be used to make cost-effectiveand CO₂-reduced concrete.

Alternatively, the ACM may be used as an alternative supplementarycementitious material (ASCM) to replace a proportion of Portland cementin conventional concrete and thereby reduce cost and environmentalimpact of resulting concrete.

FIG. 17 illustrates a typical Portland cement plant 1702 in which thecement may typically be shipped over long distances to reach concretebatch plants 1704. Similarly, aggregate from quarries 1706 may also beshipped long distances to reach their destination at concrete batchplants 1704. The time and energy to ship these dense and voluminousproducts dramatically increases the cost associated with manufacturingconcrete as well as contributes to the overall CO₂ emissions associatedwith concrete production.

FIG. 18 illustrates an alternative arrangement 1800 that utilizes theACM described herein. In some instances, an ACM mini kiln 1802 can becollated at an aggregate quarry 1706 site. In this way, thealuminosilicate material mined at the aggregate quarry 1706 can beprocessed at the ACM mini kiln 1802 on-site without transporting theaggregate to a remote location. The ACM and sufficient aggregate canthen be sent to the concrete batch plant 1704, which may be in muchcloser proximity.

FIG. 19 illustrated an alternative arrangement 1900 that utilizes theACM described herein. In the illustrated embodiment, and ACM mini kiln1802 can be collocated with a concrete batch plant 1704. Accordinglyaggregate from an aggregate quarry 1706 can be delivered to the concretebatch plant 1802 and the aggregate can be used by the ACM mini kiln 1802as described herein, and also be used as the coarse aggregate in theconcrete mix.

FIG. 20 illustrates an alternative arrangement 2000 that utilizes theACM described herein. In the illustrated embodiment, an ACM mini kiln1802 is located between an aggregate quarry 1706 and a concrete batchplant 1704. In this arrangement, aggregate can be delivered to the ACMmini kiln, which utilizes the aggregate to formulate ACM as describedherein, and the ACM and additional aggregate can be shipped to aconcrete batch plant.

The mini kiln architecture allows a distributed system that takesadvantage of the smaller, and even portable nature, of the ACM minikiln. Rather than relying on a single centralized Portland cement plantthat must ship cement long distances, a number of ACM mini kilns canreplace a Portland cement plant and reduce shipping times and costsdramatically. The illustrated embodiments of FIGS. 17-20 offer anarchitecture that is nimble, efficient, and reduces waste by locatingthe ACM mini kiln in close proximity to the aggregate quarry, theconcrete batch plant, or both.

Suitable feedstock compositions and the process of converting thefeedstock to microspheroidal glassy particles have been disclosed inApplicant's applications having Ser. No. 62/867,480, filed on Jun. 27,2019 and Ser. No. 63/004,673, filed Apr. 3, 2020, the entire disclosuresof which are hereby incorporated by reference in their entirety.Suitable feedstocks are generally rocks and minerals bearing aproportion of both aluminum and silicon oxides. Ordinary constructionaggregate materials used in concrete are suitable, economic, andconveniently located for use as an ideal cement feedstock. Previously,it was not possible to make a cementitious material from such ordinarycrystalline aluminosilicate materials.

One particular advantage of using aluminosilicate aggregate as ACMfeedstock is that the material is cheaply and abundantly available.

Another particular advantage is that aluminosilicate aggregate quarriesexist widely, and generally there is no need for permitting of newquarries to make ACM by the present method in most markets.

Another particular advantage of using aluminosilicate aggregate as ACMfeedstock is that a mini kiln (for example as described in Applicant'sco-pending application having Ser. No. 63/004,673) may be collocated ator very near the aggregate quarry, or concrete batch plant, or both,thus minimizing transportation costs of cement. This great advantagecomes about because cement from large centralized kilns travels onaverage 5-10 times further than aggregate (supply of which isdecentralized); a natural consequence of widespread aggregateavailability, low price of aggregate, and high price of shippingaggregate.

Another particular advantage of using aluminosilicate aggregate as ACMfeedstock is that frequently quarries have abundant byproduct materialavailable that is “off-specification” meaning that there is no commonuse for that particular gradation, despite such materials sharinggenerally identical composition with the main quarry products. Suchbyproduct materials are very cheaply available at both crushed stoneaggregate quarries, as well as sand and gravel quarries.

Another particular advantage of the decentralized ACM mini kilns is thatcapital cost per unit of throughput is expected to be similar toconventional rotary cement kilns, though the absolute scale of capitalrequirement is on the order of 1/10^(th) what it would be for Portlandcement production.

Another particular advantage of the decentralized ACM mini kilns is thatoperating expenditures per unit of throughput are not expected to exceedthe corresponding expenses in manufacture of Portland cement. Thereby,ACM production is cost-competitive with Portland cement at a smallerscale of production yet requires 5-10 times less shipping expense.

The present disclosure further includes the following numbered clauses.

Clause 1. Solid microspheroidal glassy particles, wherein said particlescomprise one or more of the following properties: mean roundness(R)>0.8; and less than about 40% particles having angular morphology(R<0.7).

Clause 2. The particles of clause 1, wherein said particles comprise amean roundness (R) of at least 0.9.

Clause 3. The particles of clause 1 or 2, wherein less than about 30%particles, or less than about 25% particles, or less than about 20%particles, or less than about 15% particles, or less than about 10%particles have an angular morphology (R<0.7).

Clause 4. The particles of any one of clause 1 to 3, wherein saidparticles comprise the mean oxide Formula 1:(CaO,MgO)a.(Na₂O,K₂O)b.(Al₂O₃,Fe₂O₃)c.(SiO₂)d [Formula 1] wherein a isabout 0 to about 4, b is about 0.1 to about 1, c is 1, and d is about 1to about 20.

Clause 5. The particles of any one of clauses 1 to 4, wherein saidparticles comprise one or more of the following properties: (i) acontent of 45%-100%, and preferably 90-100%, X-ray amorphous solid; and(ii) molar composition ratios of (Ca,Mg)₀₋₁₂.(Na,K)_(0.05-1).(Al,Fe³⁺)₁.Si₁₋₂₀.

Clause 6. The particles of any one of clauses 1 to 5, wherein saidparticles are 40-100% X-ray amorphous, more preferably about 80 to about100% X-ray amorphous, even more preferably 100% non-crystalline.

Clause 7. The particles of any one of clauses 1 to 6, wherein saidparticles comprise less than about 10 wt. % CaO.

Clause 8. The particles of any one of clauses 1 to 6, wherein saidparticles comprise more than about 30 wt. % CaO.

Clause 9. The particles of any one of clauses 1 to 6, wherein saidparticle comprises a high-calcium content with a molar composition ofSi/(Fe3+,Al) between 1-20, and CaO content of about 10 to about 50 wt.%, preferably about 20-45 wt. %.

Clause 10. The particles of any one of clauses 1 to 6, wherein saidparticle comprises an intermediate-calcium content with a molarcomposition of Si/(Fe3+,Al) between 1-20, and CaO content of about 10 toabout 20 wt. %.

Clause 11. A cementitious reagent comprising a mixture ofmicrospheroidal glassy particles as defined in any one of clauses 1 to10.

Clause 12. A cementitious reagent comprising a mixture ofmicrospheroidal glassy particles, wherein said particles comprises oneor more of the following properties: (i) mean roundness (R)>0.8; (ii)less than about 20% particles having angular morphology (R<0.7); (iii)the oxide Formula 1 as defined in clause 4; (iv) a content of 45%-100%,and preferably 90-100%, X-ray amorphous solid; and (v) a molarcomposition ratios of (Ca,Mg)₀₋₁₂.(Na,K)_(0.05-1).(Al, Fe³⁺)₁.Si₁₋₂₀;and (vi) a low calcium content of about <10 wt. % CaO, or anintermediate calcium content of about 10 to about 20% wt. % CaO, or ahigh calcium content of >30 wt. % CaO.

Clause 13. The cementitious reagent of clause 12, wherein saidcementitious reagent is in the form of a non-crystalline solid.

Clause 14. The cementitious reagent of clause 12 or 13, wherein saidcementitious reagent is in the form of a powder.

Clause 15. The cementitious reagent of any one of clauses 12 to 14,wherein said cementitious reagent comprises particle size distributionwith D[3,2] of about 20 μm or less, more preferably 10 μm or less, ormost preferably 5 μm or less.

Clause 16. The cementitious reagent of any one of clauses 12 to 15,wherein said mixture of particles comprises the oxide Formula 1:(CaO,MgO)a.(Na₂O,K₂O)b.(Al₂O₃,Fe₂O₃)c.(SiO₂)d [Formula 1] wherein a isabout 0 to about 4, b is about 0.1 to about 1, c is 1, and d is about 1to about 20.

Clause 17. The cementitious reagent of any one of clauses 12 to 16,wherein said cementitious reagent comprises less than about 10 wt. %CaO.

Clause 18. The cementitious reagent of any one of clauses 12 to 16,wherein said cementitious reagent comprises more than about 30 wt. %CaO.

Clause 19. The cementitious reagent of any one of clauses 12 to 16,wherein the cementitious reagent is a high-calcium containingcementitious reagent with a molar composition of Si/(Fe³⁺,Al) between1-20, and CaO content of about 10 to about 50 wt. %, preferably about20-45 wt. %.

Clause 20. The cementitious reagent of any one of clauses 12 to 16,wherein the cementitious reagent is an intermediate-calcium containingcementitious reagent with a molar composition of Si/(Fe³⁺,Al) between1-20, and CaO content of about 10 to about 20 wt. %.

Clause 21. The cementitious reagent of any one of clauses 12 to 20,wherein the cementitious reagent is about 40-100% and preferably about80 to about 100% X-ray amorphous, and even more preferably 100%non-crystalline.

Clause 22. A geopolymer binder comprising a cementitious reagent asdefined in any one of clauses 11 to 21.

Clause 23. A supplementary cementitious material (SCM) comprising acementitious reagent as defined in any one of clauses 11 to 21.

Clause 24. The SCM of clause 23, comprising at least 20 wt. % of saidcementitious reagent.

Clause 25. A solid concrete, comprising a cementitious reagent asdefined in any one of clauses 11 to 20.

Clause 26. Use of the microspheroidal glassy particles as defined in anyone of clauses 1 to 10 and/or of the cementitious reagent of any one ofclauses 11 to 20, to manufacture a geopolymer binder or cement, ahydraulic cement, a supplementary cementitious material (SCM) and/orsolid concrete.

Clause 27. A method for producing a cementitious reagent fromaluminosilicate materials, comprising the steps of: (i) providing asolid aluminosilicate material; (ii) in-flight melting/quenching saidsolid aluminosilicate material to melt said material into a liquid andthereafter to quench said liquid to obtain a molten/quenched powdercomprising solid microspheroidal glassy particles; thereby obtaining acementitious reagent with said powder of microspheroidal glassyparticles.

Clause 28. The method of clause 27, wherein said method furthercomprises step (iii) of grinding said powder of microspheroidal glassyparticles into a finer powder.

Clause 29. The method of clauses 27 or 28, wherein said powder comprisesparticle size distribution with D[3,2] of about 20 μm or less, morepreferably 10 μm or less, or most preferably 5 μm or less.

Clause 30. The method of any one of clauses 27 to 29, wherein saidparticles comprise one or more of the following properties: a meanroundness (R) of at least 0.7; less than about 20% particles of angularmorphology; the oxide Formula 1 as defined in clause 4; a content of45%-100%, and preferably 90-100%, X-ray amorphous solid; molarcomposition ratios of (Ca,Mg)₀₋₁₂.(Na,K)_(0.05-1).(Al, Fe³⁺)₁.Si₁₋₂₀;and a calcium content of less than about 10 wt. % CaO.

Clause 31. The method of any one of clauses 27 to 30, wherein saidcementitious reagent comprises one or more of the following properties:is reactive in cementitious systems and/or in geopolymeric systems;delivers workable low yield stress geopolymer cement mixes below 25 Pawhen a cement paste has an oxide mole ratio of H₂O/(Na₂O,K₂O)<20]; usesa water content in cement paste such that the oxide mole ratioH₂O/(Na₂O,K₂O)<20; and delivers a cement paste with higher workabilitythan an equivalent paste with substantially angular morphology, giventhe same water content.

Clause 32. The method of any one of clauses 27 to 31, further comprisingthe step of adjusting composition of a non-ideal solid aluminosilicatematerial to a desired content of the elements Ca, Mg, Na, K, Al, Fe, andSi.

Clause 33. The method of clause 32, wherein said adjusting comprisesblending said non-ideal aluminosilicate material with a compositionadjustment material in order to reach desired ratio(s) with respect toone or several of the elements Ca, Mg, Na, K, Al, Fe, and Si.

Clause 34. The method of any one of clauses 27 to 33, further comprisingthe step of sorting said solid aluminosilicate material to obtain apowder of aluminosilicate particles of a desired size.

Clause 35. The method of any one of clauses 27 to 34, further comprisingthe step of discarding undesirable waste material from said solidaluminosilicate material.

Clause 36. The method of any one of clauses 27 to 35, wherein saidin-flight melting comprises heating at a temperature above a liquidphase temperature to obtain a liquid.

Clause 37. The method of clause 36, wherein said temperature is about1000° C. to about 1600° C., or about 1300° C. to about 1550° C.

Clause 38. The method of any one of clauses 27 to 37, further comprisingadding a fluxing material to the solid aluminosilicate material to lowerits melting point and/or to induce greater enthalpy, volume, ordepolymerization of said liquid.

Clause 39. The method of clause 38, wherein the fluxing material ismixed with said solid aluminosilicate material prior to, or during saidmelting.

Clause 40. The method of any one of clauses 27 to 39, wherein saidin-flight melting/quenching comprises reducing temperature of saidliquid below temperature of glass transition to achieve a solid.

Clause 41. The method of clause 40, wherein said in-flightmelting/quenching comprises reducing temperature of said liquid belowabout 500° C., or preferably below about 200° C. or lower.

Clause 42. The method of clause 41, wherein reducing temperature of saidliquid comprises quenching at a rate of about 10² Ks⁻¹ to about 10⁶Ks⁻¹, preferably at a rate of >10^(3.5) Ks⁻¹.

Clause 43. The method of clause 41, wherein quenching comprises a streamof cool air, steam, or water.

Clause 44. The method of any one of clauses 27 to 43, further comprisingreducing particle size of said powder of solid microspheroidal glassyparticles.

Clause 45. The method of clause 44, wherein reducing particle sizecomprises crushing and/or pulverizing said powder in any one of a ballmill, a roller mill, a vertical roller mill.

Clause 46. The method of any one of clauses 27 to 45, further comprisingseparating quenched solid particles from hot gases in a cycloneseparator.

Clause 47. An apparatus for producing microspheroidal glassy particles,comprising: a burner; a melting chamber; and a quenching chamber.

Clause 48. The apparatus of clause 47, wherein the melting chamber andthe quenching chamber are first and second sections of the same chamber,respectively.

Clause 49. The apparatus of clauses 47 or 48, wherein said apparatus isconfigured such that solid particles are flown in suspension, melted insuspension, and then quenched in suspension in said apparatus.

Clause 50. The apparatus of any one of clauses 47 to 49, wherein saidburner provides a flame heating solid particles in suspension to aheating temperature sufficient to substantially melt said solidparticles into a liquid.

Clause 51. The apparatus of any one of clauses 47 to 50, wherein saidburner comprises a flame that is fueled with a gas that entrainsaluminosilicate feedstock particles towards the melt/quench chamber.

Clause 52. The apparatus of clause 51, wherein the gas comprises anoxidant gas and a combustible fuel.

Clause 53. The apparatus of any one of clauses 47 to 52, wherein saidthe quenching chamber comprises a cooling system for providing cool airinside the quenching chamber, said cool air quenching molten particlesto solid microspheroidal glassy particles.

Clause 54. The apparatus of clause 53, wherein said a cooling systemcomprises a liquid cooling loop positioned around the quenching chamber.

Clause 55. The apparatus of any one of clauses 47 to 54, wherein theapparatus further comprises a cyclone separator to collectmicrospheroidal glassy particles.

Clause 56. The apparatus of any one of clauses 47 to 55, wherein theburner comprises at least one of a plasma torch, an oxy-fuel burner, anair-fuel burner, a biomass burner, and a solar concentrating furnace.

Clause 57. A method for producing a cementitious reagent fromaluminosilicate materials, comprising the steps of: (i) providing asolid aluminosilicate material; (ii) in-flight melting/quenching saidsolid aluminosilicate material to melt said material into a liquid andthereafter to quench said liquid to obtain a molten/quenched powdercomprising solid microspheroidal glassy particles; thereby obtaining acementitious reagent with said powder of microspheroidal glassyparticles.

Clause 58. A method for producing microspheroidal glassy particles,comprising the steps of: providing an in-flight melting/quenchingapparatus, said apparatus comprising a burner, a melting chamber and aquenching chamber; providing solid particles; flowing said solidparticles in suspension in a gas to be burned by said burner; heatingsaid solid particles into said melting chamber to a heating temperatureabove liquid phase to obtain liquid particles in suspension; quenchingsaid liquid particles in suspension to a cooling temperature belowliquid phase to obtain a powder comprising solid microspheroidal glassyparticles.

Clause 59. The method of clause 58, wherein the melting chamber and thequenching chamber are first and sections of the same chamber,respectively.

Clause 60. The method of clauses 58 or 59, wherein said heatingtemperature is about 1000° C. to about 1600° C., or about 1300° C. toabout 1550° C.

Clause 61. The method of any one of clauses 58 to 60, wherein coolingtemperature is below 500° C., or below 200° C.

Clause 62. The method of any one of clauses 58 to 61, wherein said solidparticles comprise aluminosilicate materials.

Clause 63. The method of any one of clauses 58 to 62, wherein saidburner comprises a flame that is fueled with a gas that entrains thesolid particles towards the melting chamber.

Clause 64. The method of clause 63, wherein the gas comprises an oxidantgas and a combustible fuel.

Clause 65. The method of any one of clauses 58 to 64, wherein saidquenching comprises providing cool air inside the quenching chamber.

Clause 66. The method of any one of clauses 58 to 65, further comprisingcollecting said powder with a cyclone separator.

Clause 67. Use of an apparatus comprising at least one of a plasmatorch, an oxy-fuel burner, an air-fuel burner, a biomass burner, and asolar concentrating furnace, for producing microspheroidal glassyparticles.

Clause 68. Use of an apparatus comprising at least one of a plasmatorch, an oxy-fuel burner, an air-fuel burner, a biomass burner, and asolar concentrating furnace, for producing a cementitious reagent fromaluminosilicate materials

Clause 67. All novel compounds, compositions, processes, apparatuses,systems methods and uses substantially as hereinbefore described withparticular references to the Examples and the Figures.

Headings are included herein for reference and to aid in locatingcertain sections. These headings are not intended to limit the scope ofthe concepts described therein, and these concepts may haveapplicability in other sections throughout the entire specification.

Unless otherwise indicated, all numbers expressing quantities ofingredients, reaction conditions, concentrations, properties, and soforth used in the specification and claims are to be understood as beingmodified in all instances by the term “about.” At the very least, eachnumerical parameter should at least be construed in light of the numberof reported significant digits and by applying ordinary roundingtechniques. Accordingly, unless indicated to the contrary, the numericalparameters set forth in the present specification and attached claimsare approximations that may vary depending upon the properties sought tobe obtained. Notwithstanding that the numerical ranges and parameterssetting forth the broad scope of the embodiments are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containscertain errors resulting from variations in experiments, testingmeasurements, statistical analyses and such. As used herein, the terms“about” and “approximately” may, in some examples, indicate avariability of up to ±5% of an associated numerical value, e.g., avariability of up to ±2%, or up to ±1%.

The process parameters and sequence of the steps described and/orillustrated herein are given by way of example only and can be varied asdesired. For example, while the steps illustrated and/or describedherein may be shown or discussed in a particular order, these steps donot necessarily need to be performed in the order illustrated ordiscussed. The various exemplary methods described and/or illustratedherein may also omit one or more of the steps described or illustratedherein or include additional steps in addition to those disclosed.

The preceding description has been provided to enable others skilled inthe art to best utilize various aspects of the exemplary embodimentsdisclosed herein. This exemplary description is not intended to beexhaustive or to be limited to any precise form disclosed. Manymodifications and variations are possible without departing from thespirit and scope of the present disclosure. The embodiments disclosedherein should be considered in all respects illustrative and notrestrictive. Reference should be made to any claims appended hereto andtheir equivalents in determining the scope of the present disclosure.

It will be understood that when an element such as a layer or a regionis referred to as being formed on, deposited on, or disposed “on” or“over” another element, it may be located directly on at least a portionof the other element, or one or more intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” or “directly over” another element, it may be located on at least aportion of the other element, with no intervening elements present.

Unless otherwise noted, the terms “connected to” and “coupled to” (andtheir derivatives), as used in the specification and/or claims, are tobe construed as permitting both direct and indirect (i.e., via otherelements or components) connection. In addition, the terms “a” or “an,”as used in the specification and/or claims, are to be construed asmeaning “at least one of.” For ease of use, the terms “including” and“having” (and their derivatives), as used in the specification and/orclaims, are interchangeable with and have the same meaning as the word“comprising.”

While various features, elements or steps of particular embodiments maybe disclosed using the transitional phrase “comprising,” it is to beunderstood that alternative embodiments, including those that may bedescribed using the transitional phrases “consisting” or “consistingessentially of,” are implied. Thus, for example, implied alternativeembodiments to an oxidant gas that comprises or includes oxygen includeembodiments where an oxidant gas consists essentially of oxygen andembodiments where an oxidant gas consists of oxygen.

What is claimed is:
 1. A blended cement comprising: a binder compositionincluding Portland cement, a supplemental cementitious material, andmetakaolin; and an alkali sulfate activator compound, the blended cementcomprising, as a percentage of the binder composition: from about 40 wt.% to about 60 wt. % of the Portland cement; from about 40 wt. % to lessthan about 60 wt. % of the supplemental cementitious material; up toabout 10 wt. % of the metakaolin; and up to about 7.5 wt. % of thealkali sulfate wherein the supplemental cementitious material is not aby-product of an existing industrial process, wherein the supplementalcementitious material comprises: microspheroidal glassy particles havinga mean roundness (R)>0.7 and a Sauter mean diameter D[3,2] of about 1 toabout 20 micrometers and a molar composition containing Si and Al andoptionally one or more of Fe, Ca, Mg, Na, and K, such that:${{{about}\mspace{14mu} 0.3} < \frac{Si}{{Si} + {Al} + {Fe} + {Ca} + {Mg} + {Na} + K} < {{about}\mspace{14mu} 0.6}};{and}$${{about}\mspace{14mu} 0.2} < \frac{Al}{{Si} + {Al} + {Fe} + {Ca} + {Mg} + {Na} + K} < {{about}\mspace{14mu}{0.35.}}$2. The blended cement of claim 1, wherein the microspheroidal glassyparticles are at least about 40% x-ray amorphous.
 3. The blended cementof claim 1, wherein the supplemental cementitious material includes atleast about 1 by wt. % metakaolin and is formed by melting crystallinematerials.
 4. The blended cement of claim 1, wherein the supplementalcementitious material is free of fly ash.
 5. The blended cement of claim1, comprising from about 1 wt. % to about 5 wt. % of the alkali sulfate.6. The blended cement of claim 1, wherein the alkali sulfate is selectedfrom the group consisting of anhydrous sodium sulfate, sodium sulfatedecahydrate, and potassium sulfate.
 7. The blended cement of claim 1,comprising from about 1 wt. % to about 10 wt. % of the metakaolin.
 8. Ablended cement comprising: a binder composition including Portlandcement, a supplemental cementitious material, and optionally metakaolin;and an alkali sulfate activator compound, wherein the blended cementcomprises, as a percentage of the binder composition: from about 40 wt.% to about 60 wt. % of the Portland cement; from about 40 wt. % to lessthan about 60 wt. % of the supplemental cementitious material whereinthe supplemental cementitious material is not a by-product of anexisting industrial process; up to about 10 wt. % of the metakaolin; andup to about 7.5 wt. % of the alkali sulfate.
 9. The blended cement ofclaim 8, wherein the supplemental cementitious material comprisesmicrospheroidal glassy particles having a mean roundness (R)>0.7 and amolar composition containing Si and Al and optionally one or more of Fe,Ca, Mg, Na, and K, such that:${{{about}\mspace{14mu} 0.3} < \frac{Si}{{Si} + {Al} + {Fe} + {Ca} + {Mg} + {Na} + K} < {{about}\mspace{14mu} 0.6}};{and}$${{about}\mspace{14mu} 0.2} < \frac{Al}{{Si} + {Al} + {Fe} + {Ca} + {Mg} + {Na} + K} < {{about}\mspace{14mu}{0.35.}}$10. The blended cement of claim 8, wherein the supplemental cementitiousmaterial is free of fly ash.
 11. The blended cement of claim 8,comprising from about 1 wt. % to about 5 wt. % of the alkali sulfate.12. The blended cement of claim 8, wherein the alkali sulfate isselected from the group consisting of anhydrous sodium sulfate, sodiumsulfate decahydrate, and potassium sulfate.
 13. The blended cement ofclaim 8, comprising from about 1 wt. % to about 10 wt. % of themetakaolin.
 14. The method of claim 1, wherein the supplementalcementitious material is formed by melting crystalline minerals.
 15. Themethod of claim 8, wherein the supplemental cementitious material isformed by melting crystalline minerals.
 16. The method of claim 8,wherein the supplemental cementitious material includes metakaolin. 17.The method of claim 8, wherein the supplemental cementitious materialincludes metakaolin and is formed by melting crystalline materials. 18.A blended cement comprising: a binder composition including Portlandcement, a supplemental cementitious material; and an alkali sulfateactivator compound, wherein the blended cement comprises, as apercentage of the binder composition: from about 40 wt. % to about 60wt. % of the Portland cement; from about 40 wt. % to less than about 60wt. % of the supplemental cementitious material; up to about 10 wt. % ofthe metakaolin; and up to about 7.5 wt. % of the alkali sulfate, whereinthe supplemental cementitious material is formed by melting crystallineminerals such that the supplemental cementitious material includesmicrospheroidal glassy particles having a mean roundness (R)>0.7 and aSauter mean diameter D[3,2] of about 1 to about 20 micrometers.